Method and apparatus for treating sewage

ABSTRACT

Apparatus for sewage treatment, comprising: at least one tank ( 13 ), at least one inlet branch ( 14 ) to the tank ( 13 ), at least one outlet branch ( 15 ) from the tank ( 13 ), at least one microwave generator ( 9   a ) able to subject the sewage present internally of the tank ( 13 ) to at least one temperature raising treatment, at least a cooling circuit ( 19 ) of the microwave generator ( 9   a ), at least one blowing device ( 9   b ) connected to the tank ( 13 ). Blowing device ( 9   b ) is connected to an outlet ( 26 ) of the cooling circuit ( 19 ) and sending the heated gases arriving therefrom into the tank ( 13 ).

This application claims priority to Italian Application No.MI2012A002123, filed on Dec. 13, 2012 the entire contents of which isincorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a method and apparatus for treatingsewage.

The apparatus and method, object of the invention, find application inthe zootechnical field for managing and exploiting sewage and/or wasteof animal origin.

Moreover, the present invention can find an application in the field ofwastewater treatment coming from: agricultural systems, food farmingindustry, waste management systems, systems for producing power frombiogas, residential water (foul water) treatment systems.

TECHNICAL BACKGROUND

It is known, in the industrial and agricultural fields, the use ofapparatus and methods for treating wastewater and sludge comprisingsewage in order to dispose of the undesired substances, in order toreduce the toxicity and purify such water and/or sludge in order toenable a correct recovery or disposal.

Particularly, methods and apparatus for treating residential and/orindustrial wastewater using chemical, mechanical and/or thermalprocesses configured to treat the substance in order to reduce at aminimum the presence of micropollutants, are known. Since the toxicityof the wastewater and/or sewage is at least partially caused by thepresence of pollutants, such as ammonia nitrogen NH₃ and carbon dioxidemethods/apparatus for treating sewage, capable of extracting from thelatter ammonia dissolved as NH₄ ⁺ and ensuring the abatement of theammonia nitrogen NH₃ have been introduced.

For example, a first approach described in patent applicationWO2010/0015928 A1 provides a process of extracting ammonia nitrogen(NH₃) from wastewater. The process provides the introduction of thewastewater in a reactor inside which basifying agents adapted to reactwith the wastewater for taking the pH to the natural value are supplied:so that, ammonia nitrogen contained in the wastewater tends to separatefrom the latter as a gas (NH₃). The process provides the generation of agaseous flow inside the reactor, adapted to extract ammonia nitrogendeveloped during the chemical reaction between wastewater and basifyingagents. In order to increase the ammonia nitrogen extraction efficiency,the process provides a step of heating the wastewater and a treatingstep by means of ultrasound.

Despite the method described in first solution enables to extractammonia nitrogen from wastewater, the method itself is not devoid ofdisadvantages and limitations.

De facto, the wastewater treatment by means of chemical additives makethe method expensive and difficult to control. Specifically, thetreatment by means of chemical additives is hardly manageable underconditions wherein it is necessary to treat wastewater having differentconcentrations of dissolved substances: in this case, the adjustment ofthe additive to be introduced in the substance is hardly calculatableand adaptable to diversified conditions of the liquid. It should not bedisregarded that the chemical treatment of wastewater substantiallyprevents from reusing the liquid itself, for example for producingcompost or biogas.

In a second approach described in documents U.S. Pat. No. 6,555,011 andDE102004050493, it is provided a treatment for sanitizing and purifyingbiological fluids. The method provides a first step wherein the fluidpasses through a reactor defining inside a forced passage for the fluid.Inside the reactor and at the forced passage points there are devicesadapted to sanitize the fluid. Particularly, the method provides theformation of predetermined areas with high energy density at the forcedfluid passages: in this way, when the fluid flows through the reactor,the devices are capable of energising the latter in order to purify andsanitize it.

In a third approach described in document WO 2007/115660 it is provideda method for treating sewage in order to produce a fertilizer; theobject of this method consists of removing dissolved substances,particularly ammonia nitrogen NH₃ and carbon dioxide CO₂, present in theliquid to be treated.

More particularly, the method provides the extraction of the ammonianitrogen from sewage thanks to the use of ultrasounds, and thedepuration of the stripping gases by a solution of water and sulphuricacid.

Still more particularly, the method comprises a first step ofintroducing sewage in a first tank; the sewage is treated by ultrasoundsat a frequency comprised between 0.2 MHz and 1.7 MHz. The use ofultrasounds at the specific frequency generates inside the fluid aphenomenon called cavitation which enables to degas the fluid andrelease CO₂ and NH₃ from the same. Gases (CO₂ and NH₃) released byfluid, are then introduced, by means of a compressor, in a second tank.Inside the second tank there is a solution containing sulphuric acid(H₂SO₄) which is made soluble with the gases (CO₂ and NH₃) extractedfrom first tank. Also the solution present in second tank is treated byultrasounds at a frequency of 1.7 MHz, which, in this step, enable torelease ammonium sulphate ([NH₄]2SO₄) and carbon dioxide.

Also the methods/apparatus described in second and third approaches arenot devoid of disadvantages and limitations. Particularly, these methodsare not capable of ensuring an acceptable abatement of bacteria presentin the liquid adapted to ensure a reuse of the latter for forming afertilizer.

OBJECT OF THE INVENTION

Therefore, the object of the present invention consists of substantiallyovercoming one or more of the disadvantages and/or limitations of thepreceding solutions.

A first object of the invention consists of providing a method andapparatus for treating sewage which enables to reuse the treated sewageas a substrate for producing compost and/or biogas and/or fertilizer,and promote following sewage depurations.

A further main object of the invention consists of providing a methodand apparatus for treating sewage which enable to effectively eliminatethe majority of microorganisms, such as bacteria, moulds, mould sporesand bacteria present in the sewage.

It is a further object of the invention to provide a method andapparatus for treating sewage which enable an effective extraction ofammonia nitrogen from sewage.

Then, it is an object of the invention to provide a method and apparatusfor treating sewage capable of treating sewage with a reduced energyconsumption in order to substantially reduce its operating costs.

One or more of the above described objects and which will be betterexplained in the following description, are substantially met by amethod and apparatus for treating sewage, according to one or more ofthe attached claims.

In the following, aspects of the invention will be described.

In a 1st aspect, it is provided a sewage treatment method, comprisingthe following steps:

-   -   at least one step of electrolytically treating the sewage,    -   at least one energy transfer step comprising at least one        selected from a group comprising:

a temperature raising treatment,

an ultrasound treatment,

said electrolytic treatment and energy transfer steps determining thedissociation from the sewage of gases comprising nitrogen, preferablyammonia,

-   -   at least one step of separating gases comprising nitrogen,        preferably ammonia, from the mass of sewage.

In a 2nd aspect according to the preceding aspect, the treatment andtransfer steps determine the dissociation from sewage of gasescomprising at least ammonia thanks to an oxidation and/or reductionprocess.

In a 3rd aspect according to anyone of the preceding aspects, the energytransfer step comprises a microwave electromagnetic treatment step and astep of blowing into the sewage at least one gas, particularly air,having a temperature greater than the temperature of the sewage to betreated, in order to promote the oxidation and heating of the latter.

In a 4th aspect according to anyone of the preceding aspects, the energytransfer step comprises heating the sewage for taking the latter to atemperature comprised between 25° C. and 90° C., particularly between30° and 85° C., still more particularly between 35° C. and 80° C.

In a 5th aspect according to anyone of the preceding aspects, thetreatment and transfer steps determine the degradation of the organiccompounds having a high molecular weight, present in the mass of sewageinto organic compounds having a lower molecular weight.

In a 6th aspect according to anyone of the preceding aspects, the energytransfer step comprises a step of blowing into the sewage at least onegas comprising air and/or ozone suitable for promoting the sewageoxidation.

In a 7th aspect according to anyone of the preceding aspects, theelectrolytic treatment provides the arrangement of at least twoelectrodes (11) at least partially contacting the sewage, andelectrically connected to an electric power generator (12).

In an 8th aspect according to anyone of the preceding aspects, themicrowave electromagnetic treatment comprises the generation ofmicrowaves by at least one microwave generator (9 a), particularly amagnetron.

In a 9th aspect according to the preceding aspect, microwave generator(9 a) is configured to generate waves at a frequency comprised between 1GHz and 4 GHz, particularly between 1.5 GHz and 3 GHz, still moreparticularly between 2.3 GHz and 2.6 GHz.

In a 10th aspect according to aspect 8th or 9th, the method comprises astep of cooling the microwave generator (9 a) by an air flow, andwherein the sewage heating and oxidation comprise a substep ofreintroducing into the sewage the air exiting the microwave generator (9a) cooling step.

In an 11th aspect according to anyone of the preceding aspects, duringthe electrolytic treatment step and/or during the energy transfer step,there is a step of mechanically stirring sewage.

In a 12th aspect according to anyone of the preceding aspects, theelectrolytic treatment step and energy transfer step provide thetreatment of a predetermined sewage amount for a predetermined treatmenttime.

In a 13th aspect according to the preceding aspect, the predeterminedsewage amount has a volume greater than 0.5 m³, particularly comprisedbetween 0.5 m³ and 50 m³, still more particularly comprised between 1 m³and 10 m³, and wherein the predetermined treatment time has a durationgreater than 15 minutes, particularly comprised between 15 minutes and300 minutes, still more particularly a duration comprised between 30minutes and 120 minutes.

In a 14th aspect according to aspect 12th or 13th, during theelectrolytic treatment step and energy transfer step, at least a portionof the predetermined sewage amount is caused to continuously recirculateinside a closed circuit.

In a 15th aspect according to the preceding aspect, during the step ofrecirculating the sewage inside the closed circuit, the latter passesthrough at least one forced passage, at least one between said pair ofelectrodes (11), and microwave generator (9 a) being positioned at saidforced passage in order to respectively enable to transfer the energy tothe sewage passing from said forced passage and promote the dissociationof gases comprising at least nitrogen, preferably ammonia, from sewage.

In a 16th aspect according to the preceding aspect, during the sewagecirculation step in the closed circuit, the following substeps areprovided:

-   -   forcing the sewage to pass through a plurality of consecutive        forced passages (17),    -   irradiating sewage passing through said forced passages, the        irradiating substep using electromagnetic waves generators (9 a)        operating at a series of said forced passages (17),

particularly, wherein the forcing step is such to form, at said forcedpassages (17), corresponding sewage currents having a limited thickness,not greater than 10 mm, particularly not greater than 6 mm, facing atleast a corresponding microwave generator (9 a) such as to be entirelycrossed by said electromagnetic waves.

In a 17th aspect according to anyone of the preceding aspects, theenergy treatment step comprises at least one ultrasound treatment step,following the electrolytic treatment and heating treatment steps,suitable for promoting the dissociation from the sewage of gasescomprising at least nitrogen, preferably ammonia.

In an 18th aspect according to the preceding aspect, the sewageultrasound treatment step provides to irradiate the sewage by means ofultrasonic waves having a frequency greater than 20 kHz, particularlycomprised between 25 kHz and 45 kHz, still more particularly comprisedbetween 30 kHz and 35 kHz.

In a 19th aspect according to aspect 17th or 18th, during the ultrasoundtreatment step, the method comprises a step of blowing at least one gasinside sewage, suitable for promoting the oxidation of sewage andrelease of gases comprising nitrogen, preferably ammonia, from thesewage itself.

In a 20th aspect according to the preceding aspect, gas blown during thesewage ultrasound treatment step comprises air, particularly comprisesoxygen and/or ozone.

In a 21st aspect according to anyone of aspects from 14th to 20th, theultrasound treatment step provides a substep of withdrawing a portion ofthe sewage treated in the electrolytic treatment and energy transfersteps, and a substep of integrating the sewage treated in theelectrolytic treatment and energy transfer steps, with not treatedsewage, for keeping constant said predetermined amount.

In a 22nd aspect according to anyone of aspects from 17th to 21st, theultrasound treatment has a time duration greater than 30 minutes,particularly greater than 50 minutes, still more particularly comprisedbetween 50 minutes and 300 minutes.

In a 23rd aspect according to the preceding aspect, the predeterminedsewage amount, treated during the electrolytic treatment step and theenergy transfer step, is greater than the sewage amount treated duringthe ultrasound treatment step, and wherein the ratio of thepredetermined sewage amount treated during the electrolytic treatmentstep and energy transfer step, to the sewage treated during theultrasound treatment step is greater than 2, particularly greater than3.

In a 24th aspect according to anyone of the preceding aspects, themethod comprises at least one step of collecting gases containingammonia, separated from sewage, and a following step of refining thewithdrawn gases, comprising:

-   -   blowing gases collected in an acid liquid solution,    -   forming ammonium salts by a salification of the ammonia present        in gases collected with H⁺ ions of the acid liquid solution,    -   forming a first purified gas flow containing a percentage of        nitrogen, preferably ammonia, lower than the nitrogen        percentage, preferably ammonia, present in the collected gases,    -   abating nitrogen possibly present in the first purified gas flow        for forming a second purified gas flow containing a nitrogen        percentage, preferably ammonia, less than the percentage present        in the first gas flow.

In a 25th aspect according to the preceding aspect, the method comprisesa plurality of steps of said refining steps consecutive to each other,for obtaining purified gases with lower and lower nitrogen contents,preferably ammonia.

In a 26th aspect according to aspect 24th or 25th, the method comprisesat least one step of chemically filtering the purified gases exiting thelast refining step by active carbon filters.

In a 27th aspect, it is provided an apparatus (1) for treating sewage,comprising:

-   -   at least one sewage treatment circuit (2) having at least one        inlet (3) for receiving a sewage load to be treated, and at        least one outlet (4) for enabling the expulsion of the treated        sewage;    -   at least one first tank (5) operatively active on said treatment        circuit (2), said first tank (5) comprising at least one inlet        (6) fluidically communicating with circuit (2) inlet (3), and at        least discharge outlet (7) fluidically communicating with at        least one treatment circuit (2) outlet (4);    -   at least one electrolytic cell (8) associated to first tank (5)        and configured to subject sewage, present inside or coming from        first tank (5), for promoting the formation of gases comprising        nitrogen, preferably ammonia;    -   at least one energising device (9) associated to first tank (5)        and configured to subject sewage, present inside or coming from        first tank (5), to at least one treatment selected in the group        comprising:

a temperature raising treatment,

an ultrasound treatment,

said energising device (9) being configured to enable the oxidationand/or reduction of sewage, and promote the dissociation of gasescomprising nitrogen, preferably ammonia,

-   -   at least one gas recovering circuit (10) fluidically        communicating with first tank (5), suitable for enabling a flow        of gases, comprising nitrogen, preferably ammonia, to exit first        tank.

In a 28th aspect according to aspect 27th, the apparatus comprises atleast one recirculation device (5 a) comprising:

-   -   an auxiliary tank (13),    -   an inlet branch (14) to auxiliary tank, suitable for enabling to        withdraw sewage from first tank (5), and    -   an outlet branch (15) from auxiliary tank, suitable for enabling        to reintroduce sewage into first tank (5).

In a 29th aspect according to the preceding aspect, auxiliary tank (13)of recirculating device (5 a) is positioned outside first tank (5),inlet branch (14) of auxiliary tank (13) being configured to withdrawsewage present in first tank (5) substantially at the bottom of thelatter, outlet branch (15) of auxiliary tank (13) being configured toreintroduce sewage in first tank (5) substantially at, or above, amaximum level reachable by sewage in first tank (5).

In a 30th aspect according to anyone of aspects from 27th to 29th, theelectrolytic cell (8) comprises:

-   -   at least one pair of electrodes (11) extending inside a volume        defined by first tank (5), or inside recirculating device, in        order to contact sewage,    -   at least one electric power generator (12) connected to the pair        of electrodes (11).

In a 31st aspect according to anyone of aspects from 27th to 30th,energising device (9) comprises at least one microwave generator (9 a),for example a magnetron, configured to irradiate sewage present in firsttank (5) and/or in recirculating device by executing at least partiallysaid temperature raising treatment.

In a 32nd aspect according to anyone of aspects from 28th to 31st,energising device (9) comprises at least one blowing device (9 b)connected to first tank (5) and/or to recirculating device (5 a), andconfigured to introduce in at least one of the latter, air at atemperature comprised between 25° C. and 90° C., particularly between30° C. and 85° C., still more particularly between 35° C. and 80° C., byexecuting at least partially said heat treatment.

In a 33rd aspect according to anyone of aspects from 27th to 32nd, atleast one between electrolytic cell (8) and energising device (9) isactive at said recirculating device (5 a).

In a 34th aspect according to anyone of aspects from 28th to 33rd,auxiliary tank (13) has inside at least one choke (16) suitable fordefining at least one forced passage (17) of sewage circulating in saidauxiliary tank (13).

In a 35th aspect according to the preceding aspect, auxiliary tank (13)comprises a plurality of chokes (16), each of them defines acorresponding forced passage (17) of the sewage circulating in saidauxiliary tank (13).

In a 36th aspect according to the preceding aspect, apparatus comprisesat least one microwaves generator (9 a), for example a magnetron,externally engaged to auxiliary tank (13), substantially at at least oneforced passage (17), and configured to generate electromagnetic waves inthe direction of the latter, and wherein auxiliary tank (13) comprisesat said forced passage (17), at least one window (18) radio-transparentto the frequencies of said electromagnetic radiation.

In a 37th aspect according to aspect 35th or 36th, each of said forcedpassages has a height, measured perpendicularly to the sewageadvancement direction, comprised between 15 mm and 60 mm, particularlycomprised between 20 mm and 50 mm, still more particularly comprisedbetween 25 mm and 45 mm.

In a 38th aspect according to anyone of aspects from 27th to 37th,apparatus comprises at least one sewage stirring device (20) associatedto first tank (5) and configured to move sewage present inside thelatter.

In a 39th aspect according to the preceding aspect, stirring device (20)comprises at least one helix (21) at least partially immersed in sewagepresent inside first tank (5), said stirring device (20) furthercomprising at least one motor (22) connected to helix (21) andconfigured to rotate the latter in order to move the sewage present infirst tank (5).

In a 40th aspect according to anyone of aspects from 27th to 38th, firsttank (5) defines inside a compartment having a volume greater than 0.5m³ particularly comprised between 1 m³ and 50 m³, still moreparticularly comprised between 1 m³ and 10 m³.

In a 41st aspect according to anyone of aspects from 28th to 40th,auxiliary tank (13) defines inside a compartment having a volumecomprised between 0.25 m³ and 10 m³, particularly comprised between 0.5m³ and 5 m³, still more particularly comprised between 1 m³ and 5 m³,and wherein the ratio of the compartment volume of first tank (5) tocompartment volume of auxiliary tank (13) is greater than 1,particularly greater than 2, still more particularly greater than 3.

In a 42nd aspect according to anyone of aspects from 27th to 41st,apparatus comprises at least one second tank (23) operatively active onsaid treatment circuit (2) and interposed between first tank (5) andtreatment circuit (2) outlet (4), said second tank (23) comprising atleast one inlet (24) fluidically communicating with discharge outlet (7)of first tank (5) and at least one corresponding discharge outlet (25)fluidically communicating with the at least one treatment circuit (2)outlet (4), and wherein said apparatus (1) further comprises at leastone ultrasound generator (27) configured to irradiate sewage present insecond tank (23) in order to promote the dissociation of gasescomprising at least ammonia.

In a 43rd aspect according to the preceding aspect, ultrasound generator(27) is configured to generate ultrasounds at a frequency greater than20 kHz, particularly comprised between 25 kHz and 45 kHz, still moreparticularly between 30 kHz and 35 kHz.

In a 44th aspect according to aspect 42nd or 43rd, second tank (23)comprises a gas inlet (28) to second tank (23), said gas inlet (28)being substantially positioned at the bottom of second tank (23), saidapparatus (1) comprising a blowing device (29) fluidically communicatingwith gas inlet (28) of second tank (23), suitable for blowing at leastone gas inside the latter, said gas comprising air, particularly oxygenand/or ozone.

In a 45th aspect according to the preceding aspect, blowing device (29)comprises at least one compressor (30).

In a 46th aspect according to anyone of aspects from 41st to 45th,second tank (23) defines inside a compartment having a volume greaterthan 0.2 m³, particularly comprised between 0.3 m³ and 10 m³, still moreparticularly comprised between 0.5 m³ and 5 m³.

In a 47th aspect according to the preceding aspect, the ratio of thevolume of first tank (5) compartment to volume of second tank (23)compartment is greater than 2, particularly greater than 3, still moreparticularly greater than 4.

In a 48th aspect according to anyone of aspects 41st to 47th, secondtank (23) comprises an outlet (31) substantially located at the top ofthe latter, said gas outlet (31) fluidically communicating second tank(23) to gas recovering circuit (10) in order to enable the passage ofgases containing at least ammonia from second tank (23) to gasrecovering circuit (10).

In a 49th aspect according to anyone of aspects from 27th-48th,apparatus comprises at least one third tank (32) comprising:

-   -   a lower zone (32 a) suitable for receiving a liquid phase acid        solution (A), and an upper zone (32 b) located above and        fluidically communicating with said lower zone (32 a) and        suitable for receiving a gaseous phase,    -   at least one gas inlet (33) located in proximity of a bottom of        said third tank (32), and suitable for fluidically communicating        lower zone (32 a) to gas recovering circuit (10),    -   at least one gas outlet (34) located at a top zone of third tank        (32) and suitable for fluidically communicating upper zone (32        ab) to a gas outlet line (35).

In a 50th aspect according to the preceding aspect, acid solution (A)comprises at least one of:

-   -   a diluted solution of sulphuric acid and distilled water;    -   sulphuric acid.

In a 51st aspect according to the preceding aspect, acid solution (A)comprises at least sulphuric acid and distilled water, the masspercentage of sulphuric acid present in acid solution (A) is greaterthan or equal to the mass percentage of distilled water present insidethe acid solution, particularly wherein the ratio of the mass percentageof sulphuric acid to mass percentage of distilled water present in acidsolution is greater than 1, particularly greater than 1.5.

In a 52nd aspect according to anyone of aspects from 50 to 51st, acidsolution (A) is configured to determine, following a contact with gasesarriving from inlet (33), the salification of ammonia present in saidgases with H⁺ ions of said acid solution (A) in order to generate afirst flow of purified gas comprising ammonia in a percentage smallerthan the ammonia percentage present in gases entering the third tank(32).

In a 53rd aspect according to the preceding aspect, third tank (32)comprises at least one filtration element (37) positioned in the upperzone (32 b), said filtration element (37) being configured to interceptthe first purified gas flow in order to enable the formation of a secondpurified gas flow comprising a percentage of nitrogen, particularlyammonia, less than the nitrogen percentage, particularly ammonia,present in first purified gas flow.

In a 54th aspect according to the preceding aspect, filtration element(37) comprises a recovery plate (38) having a lower surface having anarched profile showing a concavity facing the lower zone (32 a).

In a 55th aspect according to anyone of aspects from 27th to 54th,apparatus comprises at least one active carbon filter (39) operativelyactive on outlet line (35), and configured to treat the purified gasflow exiting third tank (32).

In a 57th aspect, it is provided a method of treating sewage, comprisingthe following step:

-   -   at least one step of energising sewage by at least one selected        in the group comprising:

subjecting to an ultrasound treatment,

subjecting to a microwave electromagnetic treatment,

subjecting to an electrolytic process,

in order to enable to dissociate from sewage gases comprising nitrogen,preferably ammonia,

-   -   at least one step of collecting said gases separated from        sewage,    -   at least one step of refining the collected gases, comprising        the following substeps:

blowing collected gases in an acid liquid solution (A),

forming salts of ammonium by salification of ammonia present incollected gases with H⁺ ions of the liquid acid solution,

forming a first flow of purified gas containing a percentage ofnitrogen, preferably ammonia, smaller than the nitrogen percentagepresent in collected gases,

abating nitrogen possibly present in first purified gas flow for forminga second purified gas flow containing a nitrogen percentage smaller thanthe percentage present in first gas flow.

In a 58th aspect according to the preceding aspect, the method comprisesa plurality of said refining steps consecutive to each other forobtaining purified gases having smaller and smaller contents ofnitrogen, particularly ammonia.

In a 59th aspect according to aspect 57th or 58th, the acid liquidsolution (A) comprises at least one of:

-   -   a diluted solution of sulphuric acid and distilled water,    -   sulphuric acid.

In a 60th aspect according to the preceding aspect, the acid solution(A) comprises distilled water and sulphuric acid, and wherein the ratioof the percentage of sulphuric acid to percentage of distilled waterpresent in acid liquid solution is greater than 1, particularly greaterthan 1.25, still more particularly greater than 1.5.

In a 61st aspect according to anyone of aspects from 57th to 60th,sewage energising step provides a treatment of a predetermined sewageamount.

In a 62nd aspect according to the preceding aspect, the step ofenergising the predetermined sewage amount takes a time greater than 30minutes, particularly comprised between 50 minutes and 400 minutes,still more particularly between 50 minutes and 300 minutes.

In a 63rd aspect according to aspect 61st or 62nd, the predeterminedsewage amount has a volume greater than 0.25 m³, particularly between0.5 m³ and 10 m³, still more particularly comprised between 0.5 m³ and 5m³.

In a 64th aspect according to anyone of aspects from 57th to 63rd,during the sewage energising step, said method comprises a step ofblowing at least one gas inside the sewage for promoting the oxidationof sewage and causing the gases to exit the same sewage.

In a 65th aspect according to the preceding aspect, the gas blown duringthe sewage energising step comprises air, particularly oxygen and/orozone.

In a 66th aspect according to anyone of aspects from 57th to 65th,sewage energising step provides an ultrasound treatment, at a frequencygreater than 20 kHz, particularly comprised between 25 kHz and 45 kHz,still more particularly between 30 kHz and 35 kHz.

In a 67th aspect according to anyone of aspects from 57th to 66th,method comprises a step of pre-treating the sewage, before the sewageenergising step, which comprises at least one selected in the groupamong:

-   -   a temperature raising treatment,    -   an electrolytic treatment,    -   an oxygenation treatment.

In a 68th aspect according to anyone of aspects from 57th to 67th,pre-treatment step comprises a step of blowing inside sewage at leastone gas suitable for promoting the oxidation of sewage with a followingdissociation from the latter of gases comprising nitrogen, particularlyammonia.

In a 69th aspect according to the preceding aspect, the gas blown intothe sewage has a temperature greater than the temperature of the sewageto be treated in order to promote the oxidation and heating of thelatter.

In a 70th aspect according to anyone of aspects from 67th to 69th, thepre-treatment step provides the use of an electrolytic cell (8) suitablefor enabling the dissociation from sewage of gases comprising nitrogen,preferably ammonia, by electrolysis.

In a 71st aspect according to the preceding aspect, electrolytic cell(8) comprises at least one pair of electrodes (11) connected to at leastone electric power generator (12), the electrolytic treatment stepproviding the arrangement of electrodes (11) in order to partiallycontact the sewage.

In a 72nd aspect according to anyone of aspects from 67th to 71st, thepre-treatment step provides a step of electromagnetically treating bymicrowave the sewage, suitable for enabling the heating of the latterand inducing in the sewage a chemical reaction suitable for promotingthe dissociation from the latter of gases comprising nitrogen,preferably ammonia.

In a 73rd aspect according to the preceding aspect, the microwaveelectromagnetic treatment provides the arrangement of a microwavegenerator (9 a).

In a 74th aspect according to aspect 72nd or 73rd, microwave generatoris configured to generate waves at a frequency comprised between 1 GHzand 4 GHz, particularly between 1.5 GHz and 3 GHz, still moreparticularly between 2.3 GHz and 2.6 GHz.

In a 75th aspect according to aspect 72nd or 73rd or 74th, the methodcomprises at least one step of cooling the microwave generator (9 a) byan air flow, and wherein the heating and/or oxygenation of sewage occursby blowing into the sewage the air exiting the microwave generator (9 a)cooling step.

In a 76th aspect according to anyone of aspects from 67th to 75th, thepre-treatment step comprises a step of moving and stirring sewage.

In a 77th aspect according to anyone of aspects from 72nd to 76th, themicrowave treatment step and/or step of blowing gases in sewage, heatsthe latter to take it to a temperature comprised between 25° C. and 90°C., particularly between 30° C. and 85° C., still more particularlybetween 35° C. and 80° C.

In a 78th aspect according to anyone of aspects from 67th to 77th, gasesformed during the pre-treatment step and/or during the sewage energisingstep are blown into the liquid acid solution (A) of at least onerefining step.

In a 79th aspect according to anyone of aspects from 67th to 78th,pre-treatment step provides the treatment of a predetermined sewageamount.

In an 80th aspect according to the preceding aspect, the predeterminedsewage amount treated in the pre-treatment step is greater than thepredetermined sewage amount treated in the energising step, and whereinthe ratio of the predetermined sewage amount treated in thepre-treatment step to the predetermined sewage amount treated in theenergising step is greater than 2, particularly is greater than 3.

In an 81st aspect according to aspect 79th or 80th, the predeterminedsewage quantity treated in the pre-treatment step, has a volume greaterthan 0.5 m³, more particularly comprised between 0.5 m³ and 40 m³, stillmore particularly comprised between 1 m³ and 10 m³.

In an 82nd aspect according to aspect 79th or 80th or 81st, the step ofpre-treating the predetermined sewage amount takes a time greater than15 minutes, particularly comprised between 30 and 400 minutes, stillmore particularly a time comprised between 30 minutes and 120 minutes,particularly wherein the pre-treatment step has a duration substantiallyequal to the duration of the energising step.

In an 83rd aspect according to anyone of aspects from 79th to 82nd,during the pre-treatment step, at least a portion of the predeterminedsewage amount is continuously recirculated inside a closed circuit.

In an 84th aspect according to anyone of aspects from 57th to 83rd,method comprises at least one step of expelling gases wherein thelatter, exiting the last refining step, are passed through at least oneactive carbon filter (39) suitable for treating gases in order to enableto purify the latter for releasing them in the environment.

In an 85th aspect according to anyone of aspects from 57th to 84th, thetreatment and transfer steps determine the dissociation from sewage ofgases comprising at least ammonia thanks to an oxidation and/orreduction process.

In an 86th aspect, it is provided an apparatus (1) for treating sewage,comprising:

-   -   at least one sewage treatment circuit (2) comprising at least        one inlet (3) for receiving a sewage load to be treated, and at        least one outlet (4) for enabling the sewage to be expelled,    -   at least one energising tank (23) operatively active on said        treatment circuit (2), said energising tank (23) comprising at        least one inlet (24) fluidically communicating with circuit (2)        inlet (3) and at least one discharge outlet (25) fluidically        communicating with at least the outlet (4) of the treatment        circuit (2),    -   at least one energising device (27 a) associated to said        energising tank (23) and configured to transfer energy to the        sewage present inside the latter for promoting the formation of        gases comprising nitrogen, preferably ammonia, energising device        (27 a) comprising at least one selected in the group comprising:

an ultrasound generator (27),

a microwave generator (9 a),

an electrolytic cell (8),

-   -   at least one gas recovering circuit (10) fluidically        communicating with the energising tank (23) for receiving said        gases,    -   at least one refining tank (32) comprising:

a lower zone (32 a), suitable for receiving a liquid phase acid solution(A), and an upper zone (32 b), positioned above and fluidicallycommunicating with said lower zone (32 a) and suitable for receiving agaseous step,

at least one gas inlet (33), positioned in proximity with a bottom ofsaid refining tank (32) and suitable for fluidically communicating thelower zone (32 a) to the gas recovering circuit (10),

at least one gas outlet (34) positioned at a top zone of refining tank(32) and suitable for fluidically communicating the upper zone (32 b) toa gas outlet line (35),

wherein acid solution (A) is configured to determine, following acontact with gases arriving from inlet (33):

the salification of ammonia present in said gases with H⁺ ions of saidacid solution (A),

the generation of a first purified gas flow comprising nitrogen,preferably ammonia, in a percentage smaller than the percentage ofnitrogen, preferably ammonia, present in gases entering refining tank(32),

said refining tank (32) comprising at least one filtration element (37)positioned in the upper zone (32 b), said filtration element (37) beingconfigured to intercept first purified gas flow and enable to form asecond purified gas flow comprising a nitrogen percentage, preferablyammonia, lower than the nitrogen percentage, preferably ammonia, presentin the first purified gas flow.

In an 87th aspect according to the preceding aspect, apparatus comprisesa plurality of consecutive refining tanks (32) and fluidicallycommunicating to each other, configured to obtain purified gases havinglower and lower ammonia contents.

In an 88th aspect according to aspect 86th or 87th, acid solution (A)comprises at least one of:

-   -   a diluted solution of sulphuric acid and distilled water;    -   sulphuric acid.

In an 89th aspect according to the preceding aspect, acid solution (A)comprises at least sulphuric acid and distilled water, the percentage ofsulphuric acid in the acid solution (A) is greater than or equal to thedistilled water percentage present in the acid solution, particularlywherein the ratio of sulphuric acid percentage to distilled waterpercentage present in acid solution is greater than 1, particularlygreater than 1.5.

In a 90th aspect according to anyone of the preceding aspect from 86thor 89th, filtration element (37) comprises a recovery plate (38) havinga lower surface with an arched profiled showing a concavity facing thelower zone (32 a).

In a 91st aspect according to anyone of aspects from 86th to 90th,energising device comprises an ultrasound generator (27) suitable forgenerating ultrasonic waves at a frequency greater than 20 kHz,particularly comprised between 25 kHz and 45 kHz, still moreparticularly between 30 kHz and 35 kHz.

In a 92nd aspect according to anyone of aspects from 86th to 91st,energising tank (23) comprises a gas inlet (28) to energising tank (23),said gas inlet (28) being substantially positioned at the bottom ofsecond tank (23), said apparatus (1) comprising a blowing device (29)fluidically communicating with gas inlet (28) of second tank (23)suitable for blowing at least one gas into the latter.

In a 93rd aspect according to the preceding aspect, gas blown inenergising tank comprises air, particularly oxygen and/or ozone.

In a 94th aspect according to the preceding aspect, blowing device (29)comprises at least one compressor (30).

In a 95th aspect according to anyone of aspects from 86th to 94th,energising tank (23) defines a compartment having a volume comprisedbetween 0.25 m³ and 10 m³, particularly comprised between 0.5 m³ and 5m³, still more particularly comprised between 1 m³ and 3 m³.

In a 96th aspect according to anyone of aspects from 86th to 95th,energising tank (23) comprises a gas outlet (31) substantiallypositioned at the top of the latter, said gas outlet (31) fluidicallycommunicating second tank (23) to gas recovering circuit (10) to enablethe gases containing at least ammonia, to pass from second tank (23) togas recovering circuit (10).

In a 97th aspect according to anyone of aspects from 86th to 96th,apparatus comprises:

-   -   at least one pre-treatment tank (5) operatively active on said        treatment circuit (2) and located upstream energising tank (23),        said pre-treatment tank (5) comprising at least one inlet (6)        fluidically communicating with circuit (2) inlet (3), and at        least one discharge outlet (7) fluidically communicating with        energising tank (23) inlet (23),    -   at least one pre-treatment device (8 a) associated to the        pre-treatment tank (5) and configured to transfer energy to        sewage present inside the latter (5) for promoting the formation        of gases comprising nitrogen, preferably ammonia.

In a 98th aspect according to the preceding aspect, pre-treatment device(8 a) is configured to subject the sewage, present inside thepre-treatment tank (5), to at least one treatment selected in the groupcomprising:

a temperature raising treatment,

an ultrasound treatment,

said pre-treatment device (8 a) being configured to enable the oxidationof sewage and promote the dissociation of gases comprising nitrogen,preferably ammonia.

In a 99th aspect according to aspect 97th or 98th, pre-treatment device(8 a) comprises at least one electrolytic cell having at least one pairor electrodes (11) at least partially contacting sewage present inpre-treatment tank (5), said electrolytic cell (8) further comprising atleast one electric power generator (12) connected to the pair ofelectrodes (11) and configured to transfer electric power to the latter.

In a 100th aspect according to aspect 97th or 98th or 99th,pre-treatment device comprises at least one microwave generator (9 a),for example a magnetron, configured to irradiate sewage present inpre-treatment tank (5).

In a 101st aspect according to anyone of aspects from 97th to 100th,pre-treatment device (8 a) comprises at least one blowing device (9 b)configured to introduce air in sewage present in pre-treatment tank (5),the air introduced by blowing device (9 b) having a temperature greaterthan the temperature of sewage to be treated.

In a 102nd aspect according to anyone of aspects from 86th to 101st,first tank (5) comprises at least one recirculating device (5 a) having:

-   -   an auxiliary tank (13),    -   an inlet branch (14) to the auxiliary branch suitable for        enabling to withdraw sewage from first tank (5), and    -   an outlet branch (15) from auxiliary branch suitable for        enabling to reintroduce sewage inside first tank (5).

In a 103rd aspect according to the preceding aspect, auxiliary tank (13)of recirculating device (5 a) is positioned outside first tank (5),inlet branch (14) of auxiliary tank (13) being configured to withdrawsewage present in first tank (5) substantially at the bottom of thelatter, outlet branch (15) of auxiliary tank (13) being configured toreintroduce sewage in first tank (5) substantially at or above a maximumreachable level of sewage in first tank (5).

In a 104th aspect according to aspects 102nd or 103rd, at least onebetween electrolytic cell (8) and said microwave generator (9 a) isactive at the recirculating device (5 a).

In a 105th aspect according to anyone of aspects from 100th to 104th,auxiliary tank (13) has inside at least one choke (16) suitable fordefining a first passage (17) of the sewage circulating in saidauxiliary tank (13).

In a 106th aspect according to the preceding aspect, auxiliary tank (13)comprises a plurality of chokes (16) each of them defines a respectiveforced passage (17) of the sewage circulating in said auxiliary tank(13).

In a 107th aspect according to aspect 105th or 106th, apparatuscomprises at least one microwave generator (9 a), for example amagnetron, outwardly engaged to the auxiliary tank (13), substantiallyat least at a forced passage (17), and configured to generateelectromagnetic waves in the direction of the latter, and whereinauxiliary tank (13) comprises at said forced passage (17), at least onewindow (18) radio-transparent to said electromagnetic radiation.

In a 108th aspect according to anyone of aspects from 86th to 107th,apparatus comprises at least one sewage stirring device (20) associatedto pre-treatment tank (5) and configured to move sewage present insidethe latter.

In a 109th aspect according to the preceding aspect, stirring device(20) comprises at least one helix (21) at least partially immersed insewage present inside the pre-treatment tank (5), said stirring device(20) further comprising at least one motor (22) connected to helix (21)and configured to rotate the latter in order to move sewage present inpre-treatment tank (5).

In a 110th aspect according to anyone of aspects from 86th to 109th,pre-treatment tank (5) defines a compartment having a volume greaterthan 0.5 m³ particularly between 1 m³ and 40 m³, still more particularlycomprised between 1 m³ and 10 m³.

In a 111th aspect according to anyone of aspects from 97th to 110th,said auxiliary tank (13) defines inside a compartment having a volumegreater than 0.25 m³, particularly comprised between 0.5 m³ and 10 m³,still more particularly comprised between 1 m³ and 5 m³, and wherein theratio of the first tank (5) compartment volume to the auxiliary tank(13) compartment volume is greater than 1, particularly greater than 2,still more particularly greater than 3.

In a 112th aspect, it is provided an apparatus for treating sewage,comprising:

-   -   at least one tank (13),    -   at least an inlet branch (14) to tank (13),    -   at least an outlet branch (15) from tank (13),    -   at least one microwave generator (9 a) suitable for subjecting        the sewage, present inside tank (13), to at least a temperature        raising treatment,    -   at least one cooling circuit (19) of microwave generator (9 a),    -   at least one blowing device (9 b) connected to tank (13), said        blowing device (9 b) being connected to a cooling circuit (19)        outlet (26), and supplying heated gas from the latter to tank        (13).

In a 113th aspect according to the preceding aspect, apparatus comprisesat least one electrolytic cell (8) associated to tank (13) and having:

-   -   at least one pair or electrodes (11) extending inside the volume        defined by tank (13), and configured to at least partially        contact said sewage,    -   at least an electric power generator (12) connected to said pair        of electrodes (11),

the electrolytic cell being configured to energise at least a portion ofsewage present inside tank (13) and promote the oxidation and/orreduction of organic matter of said sewage by electrolysis.

In a 114th aspect according to aspect 112nd or 113rd, microwavegenerator (9 a) comprises at least one magnetron (9 a) configured toirradiate sewage present in tank (13) by at least partially executingthe temperature raising treatment.

In a 115th aspect according to the preceding aspect, microwave generator(9 a) is configured to irradiate fluid with electromagnetic waves havinga frequency greater than 1 GHz, particularly comprised between 1 and 3GHz, still more particularly comprised between 2.3 and 2.6 GHz.

In a 116th aspect according to anyone of aspects from 112nd to 115th,tank (13) has inside at least one choke (16) suitable for defining atleast one forced passage (17) of the sewage circulating in said tank(13), particularly wherein tank (13) comprises a plurality of chokes(16), each of them defining a respective forced passage (17) of sewagecirculating in said tank (13).

In a 117th aspect according to the preceding aspect, forced passages(17) have a height, measured perpendicularly to the advancementdirection of sewage, comprised between 15 mm and 60 mm, particularlycomprised between 20 mm and 50 mm, still more particularly comprisedbetween 25 mm and 45 mm.

In a 118th aspect according to anyone of the preceding aspects from112nd to 117th, apparatus comprises at least one among said microwavegenerator (9 a) and said electrolytic cell (8) is engaged at forcedpassage (17) and is configured to energise sewage passing through saidforced passage (17).

In a 119th aspect according to anyone of aspects from 114th to 118th,microwave generator (9 a) is outwardly engaged to tank (13),substantially at at least one forced passage (17), and is configured togenerate electromagnetic waves in the direction of the latter, andwherein tank (13) comprises, at said forced passage (17), at least onewindow radio-transparent to frequencies of said electromagneticradiations (18).

In a 120th aspect according to anyone of aspects from 112th to 119th,tank (13) defines inside a compartment having a volume greater than 0.25m³, particularly comprised between 0.5 m³ and 10 m³, still moreparticularly comprised between 1 m³ and 5 m³.

In a 121st aspect according to anyone of aspects from 112nd-120th, gasblown inside tank (13) by said blowing device (9 b) comprises air,particularly oxygen and/or ozone.

In a 122nd aspect according to anyone of aspects from 112nd to 121st,apparatus comprises:

-   -   at least one bypass branch (53) hydraulically connected to inlet        branch (14) and outlet branch (15),    -   at least one discharge outlet (54) suitable for fluidically        communicating the inner volume of tank (13) to bypass branch        (53),    -   at least one intercepting element (55) operatively active on        said discharge outlet (54) and configured to be arranged in a        first operative condition, wherein said intercepting element        (55) shuts off the passage of sewage through said discharge        outlet (54), said intercepting element (55) being further        configured to be arranged in a second operative condition        wherein said intercepting element (55) enables the sewage to        pass through the discharge outlet (54).

In a 123rd aspect according to anyone of aspects from 112nd to 122nd,apparatus comprises a sensor operatively active on tank (13) and atleast one control unit (49) connected to said sensor, said control unitbeing configured to:

-   -   receive at least one signal from sensor,    -   process said signal for determining at least one parameter based        on the sewage circulating inside said tank (13), for example        sewage pressure and/or temperature.

In a 124th aspect according to the preceding aspect, control unit (49)is configured to establish, following the reception of the signal fromsensor, the existence of a clogged condition of tank (13), control unit(49) being connected to intercepting element (55) and being configuredto supply a command signal for commanding the first or second conditionof the latter, said control unit (49) being configured to positionintercepting element (55) in second operative condition following thepresence of clogged condition of tank (13) for enabling the sewage toexit bypass branch.

In a 125th aspect, it is provided the use of an apparatus according toanyone of the preceding aspects for treating sewage, particularly sewageof animal origin.

In a 126th aspect according to the preceding aspect, blowing device (9b) supplies tank (13) with gas at a temperature greater than temperatureof sewage entering tank (13), particularly greater than an averagetemperature of sewage present in the same tank.

In a 127th aspect according to the preceding aspect, blowing device (9b) supplies tank (13) with gas at a temperature comprised between 25° C.and 90° C., particularly between 30° C. and 85° C., still moreparticularly between 35° C. and 80° C.

BRIEF DESCRIPTION OF THE DRAWINGS

Some embodiments and some aspects of the invention will be described inthe following with reference to the attached drawings, supplied only inan exemplifying and non limiting way, wherein:

FIG. 1 schematically shows in a non limiting way a first embodiment ofan apparatus for treating sewage;

FIG. 2 schematically shows in a non limiting way a second embodiment ofapparatus for treating sewage;

FIG. 3 schematically shows in a non limiting way a third embodiment ofapparatus for treating sewage;

FIG. 4 schematically shows in a non limiting way a fourth embodiment ofapparatus for treating sewage;

FIG. 4A schematically shows in a non limiting way a fifth embodiment ofapparatus for treating sewage;

FIG. 5 particularly shows a component of the apparatus outlined in FIG.4;

FIG. 5A particularly shows an embodiment variant of the component ofapparatus in FIG. 4;

FIG. 6 schematically shows in a non limiting way a sixth embodiment ofapparatus for treating sewage;

FIG. 7 shows a detail of apparatus in FIG. 6;

FIG. 7A shows an embodiment variant of the detail in FIG. 7;

FIG. 8 schematically shows in a non limiting way a seventh embodiment ofapparatus for treating sewage;

FIG. 9 schematically shows in a non limiting way an eighth embodiment ofapparatus for treating sewage.

DETAILED DESCRIPTION

Apparatus for Treating Wastewater Comprising Sewage.

Referring to attached drawings, 1 generally shows an apparatus fortreating sewage. Such apparatus 1 can be applied for example in thezootechnical field for treating sewage from a breeding farm. Moregenerally, apparatus 1 can be used in the agricultural and/or industrialand/or residential fields for treating (purifying) wastewater and/orcorresponding sludge.

In the following description, it will be made reference, in a nonlimiting way, to the treatment of sewage: however, the present apparatus1 use is not exclusively limited to the treatment of zootechnical sewage(it is not excluded the use of apparatus for treating residential,industrial, and urban wastewater).

Before describing apparatus 1, it is advantageous to specify that thesubstances to be treated contain large amounts of nitrogen N presentunder all its forms (chemical compositions).

The nitrogen bond with further elements can generate toxic and pollutingcompounds. Particularly, when nitrogen is bonded to oxygen, it ispossible to obtain oxides of ammonium (for example NO₂) which is anextremely toxic gas. When nitrogen is bonded to hydrogen, it is possibleto obtain, for example, ammonia (NH₃), which is a compound extremelytoxic for all the living beings or living organisms.

Apparatus 1 is configured to enable to extract nitrogen present insewage (alternatively in wastewater) for example as ammonia, NH₄ ⁺ ions,nitrogen oxides or as an organic form; apparatus 1 is capable ofensuring the abatement of nitrogen contained in the wastewater (varyingbased on the type of wastewater and concentration of the suspendedand/or dissolved substances) in order to reduce in this way theirpolluting capability. Preferably, apparatus 1 is configured to enable toextract ammonia (ammonia nitrogen NH₃ as a gas) dissolved in sewage (forexample as NH₄ ⁺ ions); apparatus 1 is capable of ensuring the abatementof ammonia nitrogen contained in wastewater (varying based on thewastewater type and concentration of suspended and/or dissolvedsubstances) in order to reduce the polluting capability and ensuring,for example, its reuse.

Apparatus 1 comprises a treatment circuit 2 suitable for enabling towithdraw and discharge sewage; circuit 2 comprises an inlet 3 (definingthe sewage entering point) fluidically communicating with an outlet 4from which the treated sewage is expelled.

Treatment circuit 2 comprises a loading connection or port 2 ahydraulically connectable to a sewage source S (alternatively, to watersources whose quality has been impaired by residential, industrial, oragricultural activities) such as for example basins, reservoirs and/orthe like. Connection 2 a substantially defines inlet 3 of treatmentcircuit 2, provided for withdrawing sewage from source S andtransferring it to different components of apparatus 1, which will bebetter illustrated in the following of the present description.

As it is shown in FIGS. 6 and 9, treatment circuit 2 comprises at leastone sewage withdrawing line 44 hydraulically connected to connection 2 a(fluidically communicating with inlet 3 of treatment circuit 2) andconsequently to sewage source S. Treatment circuit 2, comprises in a nonlimiting way, a feeding line 45 hydraulically connected to a watersource.

Sewage withdrawing line 44 and feeding line 45 merge in an inlet line46. As it is schematically shown in FIG. 6, both withdrawing line andfeeding lines are respectively provided with a first and second pumps47, 48 configured to enable to respectively withdraw sewage and waterand configured to feed both to the inlet line of circuit 2. The waterintroduction in treatment circuit 2 enables both to dilute sewage (dueto the introduction of water it is obtained a more liquid andhomogeneous mixture than the source sewage) and rinse (clean) treatmentcircuit 2.

The viscosity of the fluid to be treated affects the capacity of theliquid to release dissolved gases, particularly the greater theviscosity of the liquid to be treated, the greater the resistance of thesame to the gas release. Actually, the sewage “diluting” action enablesto optimize the treatment of the same in order to increase the capacityof the sewage of releasing gases (viscosity reduction).

Moreover, sewage passing through treatment circuit 2 can cause scalingformations inside the latter with a consequent clogging of the passagesewage lines. The sewage capacity of scaling the passage lines issubstantially based on the viscosity of the latter: the greater theviscosity of sewage, the greater the capacity of the latter to clog thetreatment circuit 2. The rinsing step (cleaning of the treatmentcircuit) will be better described in the following.

As shown in FIG. 8, apparatus 1 can be provided with at least onecontrol unit 49 at least connected to pumps 46 a, 47, 48. Control unit49 is configured to manage said pumps for arranging them in an operativeand stoppage conditions: in this way control unit 49 manages the sewageand water withdrawal from the corresponding sources and the feeding ofthe mixtures through the inlet branch 46.

Control unit 49 can be configured to manage, by the control of the firstand second pumps 47, 48, the dilution level of sewage and/or the circuit2 rinsing. For example, control unit 49 can be configured to manage thefed fluid flow rate of first and second pumps 47, 48 and/or manage theratio of water amount to sewage amount.

As it is shown in FIG. 6, apparatus comprises, in a non limiting way, apump 46 a operative on inlet line 46, configured to receive the sewageand water mixture from withdrawing and feeding lines 44, 45 and feed itto a first or pre-treatment tank 5.

As it is shown in the FIG. 6 outline, apparatus 1 can comprise at leastone or more valves 68 arranged on lines 44, 45 and 46 suitable forshutting off the liquid passing through both lines. Moreover, apparatuscan comprise one or more control sensors 69 (for example a temperaturesensor and/or a pressure sensor) operatively active on lines 44, 45 and46, configured to detect, for example, the temperature and/or pressureof the liquid circulating inside the latter.

First or pre-treatment tank 5 is operatively active on treatment circuit2 and is configured to receive the sewage and water mixture from inletline 46.

From a structural point of view, first tank 5 comprises, in a nonlimiting way, a silos having a substantially cylindrical shape andextending, in an operative condition of first tank 5, along a verticaldirection.

FIGS. 1-4 show a preferred arrangement of first tank 5 having acylindrical shape (silos) while FIG. 4a shows, in a non limiting way, anembodiment variant of the first tank 5 having a parallelepiped shapeextending, in an operative condition of first tank, mainly along adevelopment direction substantially horizontal.

De facto, first or pre-treatment tank 5 comprises a container having acircular profile bottom wall, a side cylindrical wall perimetrallyconnected to bottom wall and an upper wall located on the top of sidewall.

First tank 5 defines inside a compartment 40 having a volume greaterthan 0.8 m³, particularly greater than 10 m³, still more particularlycomprised between 1 and 50 m³.

As it is for example shown in FIGS. 1-4 a, first tank 5 comprises atleast one inlet 6 fluidically communicating with inlet line 46 oftreatment circuit 2 which enables to feed sewage (particularly sewageand water mixture) into first tank 5. The arrangement of inlet 6 onfirst tank 5 affects the necessary thrust provided to sewage andproduced by pump 46 a for enabling the latter to feed sewage insidefirst tank 5.

FIGS. 1-4 a show a preferred condition of first tank 5, wherein inlet 6is arranged on side wall at the top of the latter. Specifically, inlet 6is arranged above a maximum level reachable by sewage inside first tank5: in this way, it is possible to ensure a condition wherein, despiteinside first tank 5 there is a predetermined sewage amount, the latterdoes not interfere with the sewage entering from inlet 6. This latterdescribed condition enables to minimize the pump 46 a power necessaryfor thrusting sewage. Alternatively, inlet 6 can be arranged in theupper wall of first or pre-treatment tank 5 (arrangement shown in FIG.6).

Despite the above described arrangements regarding the position of inlet6, are advantageous in terms of power of pump 46, it is not excluded thepossibility of arranging inlet 6 in the bottom wall of first tank 5.

As it is shown in FIGS. 1-4 a, first tank 5 further comprises at leastone sewage discharge 7 (sewage and water mixture) outlet 7 fluidicallycommunicating with outlet 4 of treatment circuit 2. Discharge outlet 7,in contrast with inlet 6, is advantageously located in the bottom wallof first or pre-treatment tank 5 for enabling an easy and fast expulsionof sewage contained in the latter.

As previously said, apparatus 1 is configured to treat sewage in orderto extract from the latter dissolved gases comprising nitrogen,particularly ammonia (polluting gases made of organic matter). Firsttank 5 comprises at least one gas outlet 50 fluidically communicatingwith at least one gas treatment circuit 10 in order to enable the gasesto be released from sewage. Advantageously, gas outlet 50 is arranged inthe first tank 5 top, particularly is arranged in the top wall of thelatter (see for example FIGS. 1-4 a).

As it is shown in the attached figures, first tank 5 comprises, in a nonlimiting way, a first and second gas inlets 51, 52 configured to enableto feed gases, particularly air, inside first or pre-treatment tank 5.

More in detail, first inlet 51 is positioned, in a non limiting way, inthe bottom wall of first tank 5 for enabling to feed air, particularlyoxygen and/or ozone, into the latter. Inlet 51 position enables air tocontact sewage present inside first tank. Air, particularly oxygenand/or ozone, fed from inlet 51 enables to oxidize sewage and promotethe dissociation from the latter of gases comprising nitrogen,preferably ammonia. Besides the sewage oxidation, air fed to first inlet51 supports the release of gases from sewage through gas outlet 50.

As it is shown in FIG. 6, first inlet 51 fluidically communicates withfirst gas feeding line 51 a which, in turn, fluidically communicateswith a blowing device 9 b. The attached figures show a preferredembodiment wherein first gas feeding line 51 a fluidically communicateswith the outer environment. Blowing device 9 b comprises a compressor 30configured to withdraw air from outer environment and enable to blow itinside first or pre-treatment tank 5.

Instead, with reference to second gas feeding inlet 52, it is located,in a non limiting way, in the top wall of first tank 5 (see for exampleFIG. 4) for enabling to feed air inside the latter. The arrangement ofsecond inlet 52 enables air to contact gases developed inside first tank5 and convey them to gas outlet 50. Second inlet 52 fluidicallycommunicates with a second gas feeding line 52 a which in turnfluidically communicates with a gas source. Attached figures show apreferred embodiment wherein second gas feeding line 52 a fluidicallycommunicates with the outer environment. On second gas feeding line 52 ais operatively active a compressor configured to withdraw air from theouter environment and blow it into first or pre-treatment tank 5.

Apparatus 1 comprises at least one energising device configured totransfer energy to sewage and promote the dissociation of gases in orderto enable the dissociation of said gases comprising nitrogen, preferablyammonia, in first tank 5.

FIGS. 1-4 a show different arrangements of first tank 5.

Each embodiment comprises, in a non limiting way, at least oneelectrolytic cell 8 active on first tank 5 and comprising a pair orelectrodes 11 at least partially contacting sewage present inside tank5.

Electrolytic cell 8 is configured to energise treating fluid forpromoting the dissociation from sewage at least of nitrogen for forminggases comprising the latter element, particularly ammonia.

Electrolytic cell 8, used in first tank 5, substantially acts as anenergising element suitable for promoting the oxidation-reduction insidethe fluid for releasing nitrogen, particularly ammonia. Effectively,electrolytic cell 8 substantially performs an inverse electrolysisprocess, in other words energising fluid (by applying a determinedvoltage across the electrodes) causes a chemical reaction in the fluidsuitable for dissociating nitrogen, particularly ammonia, from saidfluid.

Electrodes 11 are electrically connected to an electric generator 12adapted to supply a determined voltage across the pair of electrodes 11.Generator 12 has an electric power comprised between 1 and 20 kW, stillmore particularly comprised between 5 and 15 kW.

Such generator enables to define inside the fluid an electric currentgreater than 4 Ampere, particularly comprised between 4 and 25 Ampere,still more particularly comprised between 5 and 20 Ampere.

The amount of electric current passing through the fluid depends on thequantity and intensity of a salt bridge formed by theoxidation-reduction reaction in the fluid, which causes the dissociationof gases comprising nitrogen, particularly ammonia.

Embodiment in FIG. 1 comprises, in a non limiting way, two electrolyticcells 8 each of them is associated to the top wall of tank 5. Besidesthe electrolytic cells 8, first tank 5 in FIG. 1 is provided with, in anon limiting way, a pair of resistors 41 which are engaged to the tank 5upper wall and electrically connected to an electric generator 42.Resistors and generator 41, 42 are configured to transfer thermal energyto sewage, in other words heat the latter in order to promote thedissociation of gases comprising nitrogen, preferably ammonia. Besidesthat, heating sewage enables to make homogeneous the sewage mass whichin turn enables to increase the dissociating action of electrolyticcells 8.

Apparatus 1 comprises, in a non limiting way, a stirring device 20 whichis also engaged to the tank 5 upper wall. Stirring device 20 comprises amotor 22 engaging a helix 21 at least partially contacting the sewagepresent in first tank 5. Stirring device 20 is configured to move sewagepresent in first tank 5 in order to promote its homogenization.

In the embodiment shown in FIG. 1, first tank 5 comprises, in a nonlimiting way, a plug 43 defining the tank 5 upper wall and for exampleremovably engaged to tank 5. As it is shown in FIG. 1, plug 43 firmlysupports the inlet 52, electrolytic cells 8, resistors 41 with theircorresponding generators 42, stirring device 20, and outlet 50.

The second embodiment of first tank 5, shown in FIG. 2, is substantiallysimilar to first embodiment. In contrast to first embodiment, tank 5 isintegrally made (plug 43 is not present) and just the electrolytic cell8 is engaged to tank 5 upper wall. Electric resistors 41, withcorresponding generators 42, and stirring device 20 are engaged to tankside wall. Sewage and gas inlets and outlets are arranged, in a nonlimiting way, as in the first embodiment.

In the third embodiment shown in FIG. 3, tank 5 has a structuresubstantially similar to the structure shown in second embodiment (plug43 is not present). Inlets and outlets are effectively configured as inthe previously examined embodiments. Whereas, with reference to theelectrolytic cell 8, resistors 41 (with their corresponding generators42) and stirring device 20, are engaged to the side wall of first tank5.

The fourth embodiment, shown in FIG. 4, is substantially similar tofirst embodiment (arrangement of tank and configuration of the details).In the fourth embodiment, first tank 5 further comprises a recirculatingdevice 5 a suitable for circulating inside it at least a portion ofsewage present in first tank 5. During the circulation step, device 5 ais configured to further energise the sewage withdrawn and reintroduceit into first tank 5. Device 5 a is, effectively, an element for afurther treatment associated to first tank 5, which enables toincrease/promote the dissociation of gases comprising nitrogen. Device 5a will be better explained in the following.

The fifth embodiment of first tank 5, shown in FIG. 4a , has, in a nonlimiting way, a parallelepiped shape. As with the first embodiment shownin FIG. 1, tank 5 in FIG. 4a has a plug 43 defining the tank 5 upperwall and for example removably engaged to the latter. As for thepreviously examined embodiments, inlet 6 is located in the tank 5 topand above a maximum level reachable by sewage, while outlet 7 ispreferably positioned at the bottom wall of first tank 5.

In the fifth embodiment, first tank 5 comprises, below the inlet 6, asloped support 70 configured to receive the sewage fed through inlet 6.Support 70 comprises, in a non limiting way, a plate having mainextension direction and extending between a first end 71, constrained totank 5, and a second end 72 suspended inside first tank 5 at a levellower than the level at which first end 71 is positioned. The leveldifference (slope) of the plate enables sewage from inlet 6 to flow onthe latter to second end 72.

A pair of electrodes 11 of an electrolytic cell 8 is engaged on theplate: sewage flowing on plate is energised by the electrolytic cell 8which in turn promotes the dissociation from sewage of gases comprisingnitrogen.

In the embodiment of FIG. 4a , blowing device 9 b is positioned atsecond end 72 of plate and particularly below the latter. First inlet 51of device 9 b is positioned in the direction of sewage falling from thesecond plate end: the air and/or nitrogen on the sewage film fallingfrom plate causes an oxidation reaction in sewage, which in turnpromotes the dissociation from the latter of gases comprising nitrogen.

As for the fourth embodiment, also in the fifth embodiment, first tank 5further comprises a recirculating device 5 a (not shown in FIG. 4a )suitable for recirculating inside it at least a portion of sewagepresent in first tank 5. During the recirculating step, device 5 a isconfigured to further energise withdrawn sewage and reintroduce it intofirst tank 5. Effectively, device 5 a is a further treatment elementassociated to first tank 5, which enables to increase/promote thedissociation of gases comprising nitrogen.

From a structural point of view, device 5 a comprises: an auxiliary tank13, an inlet branch 14 to auxiliary tank 13 suitable for enabling towithdraw sewage from first tank 5, and an outlet branch 15 fromauxiliary tank, suitable for enabling to reintroduce sewage into firsttank 5.

Auxiliary tank 13 of recirculating device 5 a is positioned, in a nonlimiting way, outside first tank 5: inlet branch 14 of auxiliary tank 13is configured to withdraw sewage present in first tank 5 substantiallyat the bottom of the latter, while outlet branch 15 is configured toreintroduce sewage in first tank 5 substantially at or above a maximumlevel reachable by sewage in first tank 5. Recirculating device 5 asubstantially forms a closed circuit for recirculating sewage present infirst tank 5.

From a dimensional point of view, auxiliary tank 13 defines inside acompartment having a volume comprised between 0.1 m³ and 10 m³,particularly comprised between 0.2 m³ and 5 m³, still more particularlycomprised between 0.3 m³ and 1 m³. The ratio of the first tank 5compartment volume to auxiliary tank 13 compartment volume is greaterthan 5, particularly greater than 6, still more particularly greaterthan 8.

FIGS. 5 and 5A show, in a non limiting way, two different embodiments ofrecirculating device 5 a. To the circulating device 5 a is associated atleast one energising device suitable for treating sewage passing fromauxiliary tank 13 in order to promote the dissociation of gasescomprising nitrogen, preferably ammonia.

In the embodiment of FIG. 5, auxiliary tank 13 has inside, in a nonlimiting way, a series of chokes 16, each of them is suitable fordefining inside the auxiliary tank 13 a sewage forced passage 17.

As it is shown in the attached figures, forced passages 17 define, in anon limiting way, a substantially zigzag path: in this way forcedpassages alternately convey sewage at the facing side walls of auxiliarytank 13. However, it is not excluded the possibility of arranging forcedpassages 17, aligned along the sewage advancement direction.

FIG. 5A shows openings of forced passages 17 having, in a non limitingway, a substantially semicircular cross-section. Alternatively, forcedpassages 17 can have a polygonal, circular or elliptical cross-section.

At least one microwave generator 9 a, for example a magnetron, isoutwardly engaged to auxiliary tank 13, substantially at at least oneforced passage 17. Generator 9 a is configured to generateelectromagnetic waves in the direction of the forced passage 17 forirradiating sewage passing from the latter. Generator 9 a, as forelectrolytic cell 8 and electric resistors, enables to energise thefluid in order to promote the dissociation from the latter of gasescomprising nitrogen, particularly ammonia. Generator 9 a has a power,expressed in kW, greater than 20 kW, particularly comprised between 20and 100 kW, still more particularly comprised between 30 and 100 kW.Such generator 9 a is configured to irradiate fluid havingelectromagnetic waves at a frequency greater than 1.5 GHz, particularlycomprised between 1.5 and 2.5 GHz, preferably 2.45 GHz.

Each of the forced passage 17 has a height, measured perpendicularly tothe sewage advancement direction, comprised between 15 mm and 60 mm,particularly comprised between 20 mm and 50 mm, still more particularlycomprised between 25 mm and 45 mm. In this way, forced passage 17generates a striction wherein sewage has a thickness equal to the forcedpassage 17 height. Auxiliary tank 13 comprises, at forced passage 17, atleast one window 18 radio-transparent to frequencies of theelectromagnetic radiation. Forced passage 17 height is sized so that theelectromagnetic waves of generator 9 a can completely penetrate throughthe fluid thickness passing through said passage: in this way it ispossible to ensure the irradiation of all the material passing throughthe passage opening.

Window 18 is configured to enable microwave generator, arranged at saidwindow 18, to completely irradiate the sewage flow passing through theforced passage 17: particularly, thanks to the reduced thickness of theflow passing through each forced passage and thanks to the microwavegenerator power, the electromagnetic radiation crosses and irradiatesall the material passing through each forced passage.

FIG. 5 shows an embodiment of the recirculating device 5 a whereinmicrowave generators 9 a are, in a non limiting way, aligned along thesewage advancement direction (in this configuration, the microwavegenerators 9 a are not present on all the forced passages).

In the embodiment of FIG. 5A, at least one microwave generator 9 a isengaged at one forced passage 17. As it is shown in FIGS. 5 and 5A,circulating device 5 a further engages at least one electrolytic cell 8suitable for treating sewage passing from said auxiliary tank 13.

In the embodiment of FIG. 5, apparatus comprises, in a non limiting way,just one electrolytic cell 8 substantially positioned at the sewageoutlet from auxiliary tank 13. Particularly, electrolytic cell 8 isinterposed between chokes 16 and outlet branch 15 of auxiliary tank 13.

An alternative embodiment is shown in FIG. 5A, wherein it is present,for each of said forced passages 17, at least one electrolytic cell 8adapted to energise the sewage passing through passages 17.

As it is shown in FIG. 5, recirculating device 5 a comprises at leastone blowing device 9 b suitable for enabling to introduce gases insideauxiliary tank 13 with a following oxidation of sewage in order topromote the dissociation of gases comprising ammonia.

FIG. 5 shows a preferred embodiment of recirculating device 5 a,comprising at least one cooling circuit 19 of the microwave generators 9a associated to auxiliary tank 13.

In particular, cooling device 19 is configured to withdraw environmentair and generate an air flow adapted to heat the microwave generators:air flow absorbs heat from generators 9 a for preventing them fromoverheating.

Cooling circuit 19 is configured to convey air flow through an outlet26, positioned at the inlet branch 14 of tank 13, which introducesinside the latter, the heated air flow. In this way, it is possible tointroduce into tank 13 air at a temperature comprised between 25° C. and90° C., particularly between 30° C. and 85° C., still more particularlybetween 35° C. and 80° C.

The temperature of the sewage to be treated is reasonably lower than thetemperature of the air flow recovered from cooling circuit 19, thereforethe introduced air flow, besides enabling the oxidation of the sewage,enables to heat the latter in order to further promote the dissociationfrom sewage of gases comprising ammonia.

The presence of chokes 16 inside the auxiliary tank 13 can cause theclogging/stoppage of the same at at least one forced passage 17. Inorder to open the circulating device 5 a, it is possible to provide abypass branch 53 hydraulically connected to inlet branch 14 and outletbranch 15. Bypass branch comprises one or more discharge outlets 54adapted to fluidically communicate the inner volume of tank 13 to thebypass branch 53. Preferably, discharge outlets 54 are positioned at oneor more forced passage 17.

Each discharge outlet has at least one intercepting element 55operatively active on discharge outlet 54 and configured to take a firstoperative condition wherein intercepting element 55 shuts off sewagepassage through said discharge outlet 54. Intercepting element 55 isfurther configured to take a second operative condition, whereinintercepting element 55 enables the sewage to pass through dischargeoutlet 54.

If the recirculating device 5 a becomes clogged, it is possible toposition one or more intercepting elements 55 in the second operativecondition in order to enable the sewage to pass from the bypass branch53.

Apparatus 1 can comprise at least one sensor, for example a pressureand/or temperature and/or flow sensors, operatively active on tank 13and connected to control unit 49; control unit 49 is configured toreceive at least one sensor signal and process said signal fordetermining at least one parameter related to the sewage circulatinginside said tank 13, for example pressure and/or temperature and/or flowrate of sewage. Control unit 49 is configured to establish, followingthe reception of the sensor signal, the presence of a clogging conditionof tank 13; control unit 49 is connected to intercepting element 55 andis configured to send a command signal to the latter for commanding thefirst or second condition of the latter. Control unit 49 is configuredto position intercepting element 55 in second operative condition afterthe clogged tank 13 condition has been determined for enabling thesewage to exit the bypass branch 53.

FIG. 4 shows a condition wherein to the first tank 5 only onerecirculating device 5 a is associated, alternatively two or moredevices 5 a can be associated to first tank 5 in order to form a seriesof circulations of the sewage present in tank 5.

Following the sewage advancement direction, treatment circuit 2comprises a passage line 56 hydraulically connected, from one side, todischarge outlet 7 of first tank and, from the other side, to a secondor energising tank 23. Passage line 56 is configured to enable thesewage treated in first tank 5 and recirculating device 5 a, to flowinto second tank 23.

As schematically shown in FIG. 6, apparatus 1 comprises a pump 58configured to enable the sewage to be withdrawn from first tank 5 andsupply sewage to second tank 23. As for lines 44, 45, and 46, alsopassage line can comprise at least one valve 68 and/or control sensorcommunicating with control unit 49 in order to monitor and manage theflow passing through passage line 56.

Second or energising tank 23 is operatively active on treatment circuit2 and is configured to receive sewage arriving from first tank 5.

From a structural point of view, second tank 23 comprises, in a nonlimiting way, a silos having a substantially cylindrical shapeextending, in an operative condition of second tank 23, along a verticaldirection. Effectively, tank 23 comprises a silos having a bottom wallwith a circular outline, a cylindrical side wall perimetrally connectedto bottom wall, and a top wall positioned on the top of side wall.

Second tank 23 defines inside a compartment 59 having a volume comprisedbetween 0.1 m³ and 15 m³, particularly comprised between 0.2 m³ and 10m³, still more particularly comprised between 0.25 m³ and 1 m³.Specifically, the ratio of the volume defined by compartment 40 of firsttank 5 to volume defined by compartment 59 defined by second tank 23 isgreater than 3, particularly greater than 4, still more particularlygreater than 8.

As it is shown for example in FIG. 6, second tank 23 comprises at leastone inlet 24 fluidically communicating with passage line 56 of treatmentcircuit 2, which enables the sewage to be supplied into second tank 23.As discussed in relation to first tank 5, the arrangement of inlet 24 onsecond tank 23 controls the thrust necessary to the sewage, delivered bypump 58 in order to enable the latter to supply the sewage into secondtank 5 (energising tank). FIG. 6 shows a preferred condition of secondtank 23 wherein inlet 24 is arranged on top wall of the latter. Defacto, as for inlet 6 of first tank, inlet 24 is arranged above amaximum level reachable by sewage inside the second tank 23: in thisway, it is possible to ensure a condition wherein, despite second tank23 contains a predetermined sewage amount, the latter does not interferewith the sewage entering from inlet 24.

As it is shown in FIG. 6, second tank 23 further comprises at least onedischarge outlet 25 of sewage (sewage and water mixture) fluidicallycommunicating with outlet 4 of treatment circuit 2. As opposed to inlet24, discharge outlet 25 is advantageously positioned at tank 23 bottomwall in order to enable a sewage present in the latter to be easily andquickly expelled.

As previously said, apparatus 1 is configured to treat sewage in orderto extract dissolved gases comprising nitrogen (polluting gases of theorganic matter), preferably ammonia. Second tank 23 comprises at leastone gas outlet 31 fluidically communicating with at least the gastreatment circuit 10 in order to enable the gases to be released fromsewage. Advantageously, gas outlet 31 is arranged at the top of secondtank 23, particularly is arranged on the upper wall of the latter (forexample, see FIG. 6).

As it is shown in the attached figures, second tank 23 comprises, in anon limiting way, a gas inlet 28 configured to enable to supply gasinside second tank 23, particularly air, still more particularly oxygenand/or ozone.

More in detail, inlet 31 is positioned, in a non limiting way, in thebottom wall of second tank 23 to enable to supply air, particularlyoxygen and/or ozone, inside the latter. The arrangement of inlet 31enables the air to act on sewage present inside second tank 23. Air,particularly oxygen and/or ozone, entering the inlet 31 enables tooxidize the sewage in order to promote the dissociation from the latterof gases comprising nitrogen, preferably ammonia. Besides the sewageoxidation, the air introduced from inlet 31 enables said gases to bereleased from sewage.

As it is shown in FIG. 6, inlet 31 fluidically communicates with a gassupply line 60 which in turn fluidically communicates with a blowingdevice 29. Attached figures show a preferred embodiment wherein gassupply line 60 fluidically communicates with the outer environment.Blowing device 29 comprises a compressor configured to withdraw air fromouter environment and enable to blow the air inside second tank 23.

Apparatus 1 comprises at least a further energising device configured totransfer energy to sewage and promote the dissociation of said gases,comprising ammonia, in order to enable the dissociation of gasescomprising nitrogen, preferably ammonia, in second tank 23. Inparticular, the energising device associated to second tank, comprisesat least one ultrasound generator 27 suitable for generating ultrasonicwaves at a maximum frequency greater than 20 kHz, particularly comprisedbetween 25 kHz and 45 kHz, still more particularly between 30 kHz and 35kHz, and preferentially a frequency of about 32.5 kHz. In a preferredembodiment, the ultrasound irradiation is performed by varying the wavesfrequency from a minimum frequency to the above mentioned maximumfrequency: in this way it is possible to maximize the disgregatingeffect of ultrasound on ammonia.

De facto, an ultrasound continuous irradiation would cause a sewagestratification and would adapt the same to the treatment: in this waythe sewage would be adapted at a molecular level to the ultrasonic wavesso that the cavitation phenomenon inside the sewage will be reduced.

On the contrary, a continuous variation of the ultrasonic wavesfrequency prevents the sewage from adapting to the treatment: so that itis possible to maintain intense the fluid cavitation phenomenon.

The Applicant has observed that the ultrasound treatment, if performedafter the pre-treatment step by microwaves and electrolytic cells,entails an unexpected and surprising capability to separate ammoniaprobably due to different factors: for example, the materialhomogenization and pre-treated material heating certainly promote thepropagation of ultrasounds so that the cavitation phenomenon in theliquid (sewage) is boosted in comparison with a non “pre-treated”liquid.

Ultrasonic irradiation with ultrasonic wave represents the treatment atthe end of which sewage is discharged as a product denatured of theammonia nitrogen fraction. Ultrasonic irradiation generates inside thesewage a cavitation process causing, at a chemical level, conditionsadapted to the passage of gas of ammonia dissolved in water to a gasstate. The process can be defined as an “sonic-chemical” process: theaim consists of forming as small as possible cavitation bubbles in orderto boost the ammoniacal gases transfer to the surface of the basin sothat they can be sucked. This step can be made more effective by meansof the preceding pre-treatment actions.

Treatment circuit 2 comprises a discharge line 61 hydraulicallyconnected to discharge outlet 25 of second tank 23. Discharge line 61enables to expel treated sewage from treatment circuit 2. In theembodiment of FIG. 6, on discharge line 61 is active a pump 62 adaptedto withdraw treated sewage from second tank 23 and supply it, forexample, to a collection basin 63.

It is useful to specify that both tanks (first and second tanks 5, 23)do not comprise any type of systems supplying vapours or gases in theatmosphere, thanks to the presence of hoods collecting vapours conveyedin forced conduits.

In the preferred embodiment of apparatus 1, first and second tanks 5, 23are substantially distinct from each other and are connected to eachother by means of passage line 56. Alternatively, first and second tanks5, 23 are united to each other so that they define just one tank.

Further, apparatus 1 can comprise an oxidation tank 77 schematicallyshown in FIG. 8, fluidically communicating with second tank 23 and whichis suitable for receiving sewage exiting from the latter.

In particular, it is possible to provide an oxidation line 78hydraulically connected to discharge line 25 of second tank 23. A pump79 present on oxidation line 78 is configured to enable the sewage to bewithdrawn from second tank 23 and supply it to oxidation tank 77.Oxidation line 78 can also comprise at least one control valve and/orsensor communicating with control unit 49 in order to monitor and managethe flow passing through said oxidation line 78.

From a structural point of view, oxidation tank 77 comprises, in a nonlimiting way, a silos having a substantially cylindrical shape andextending, under the operative condition of tank 77, along a verticaldirection. Effectively, tank 77 comprises a container having a bottomwall having a circular outline, a cylindrical side wall perimetrallyconnected to bottom wall, and a top wall located on the top of sidewall.

Tank 77 defines inside a compartment 80 having a volume comprisedbetween 0.1 m³ and 15 m³, particularly comprised between 0.2 m³ and 10m³, still more particularly comprised between 0.25 m³ and 1 m³.

As it is shown for example in FIG. 8, tank 77 comprises at least oneinlet 81, fluidically communicating with discharge outlet 25 of secondtank 23, which enables the sewage to be supplied into the same tank 77.

As it is shown in FIG. 8, tank 77 comprises a circulating line 82configured to enable the sewage to be withdrawn from bottom of tank 77and configured to supply it at the top of said tank where thecirculating line defines a second inlet 83.

Oxygenation tank 77 comprises a sloped support 84 configured to receivesewage supplied through second inlet 83. Support 84 comprises, in a nonlimiting way, a plate 85 having a main extension direction extendingbetween first end 86, constrained to tank 77, and a second end 87,suspended inside tank 77 at a level lower than the level at which firstend is located. The level difference (slope) of plate 85 enables thesewage, arriving from second inlet, to flow on the latter to the secondend 72.

Further, tank 77 comprises a blowing device 88 positioned at secondinlet 87 of plate 85 and particularly positioned below the latter.Blowing device 88 comprises a supply opening 89 directed towards sewagefalling from second end 87 of plate 85: blowing air and/or nitrogen onthe sewage film falling from the plate, causes a sewage oxidationreaction which promotes the dissociation from the latter of gasescomprising nitrogen.

Gases exit an outlet line 90 fluidically communicating with gasrecovering circuit and suitable for withdrawing gases comprisingnitrogen dissociating from sewage.

The energy treatments/transfers performed in first and second tanks 5,23, and oxidation treatment performed in tank 77 enable to form gases,comprising nitrogen, particularly comprising ammonia, which arecollected inside the gas recovering circuit 10. Particularly, said gasesare recovered thanks to a compressor 64 operatively active on said gasrecovering circuit 10 and configured to supply said gases towards a gasinlet line 66.

Gas inlet line 66 fluidically communicates with third or refining tank32 configured to collect and purify the recovered gases.

From a structural point of view, third tank 32 comprises, in a nonlimiting way, a silos having a substantially cylindrical shapeextending, in an operative condition of third tank 32, along a verticaldirection. In the shown example, tank 32 comprises a container having abottom wall with a circular outline, a cylindrical side wallperimetrally connected to bottom wall, and an upper wall located on topof side wall.

Third tank 32 defines a compartment 67 having a volume comprised between0.25 m³ and 10 m³, particularly comprised between 0.5 m³ and 1 m³.

Third tank 32 comprises a lower zone 32 a adapted to receive an acidsolution A in a liquid phase, and an upper zone 32 b positioned aboveand fluidically communicating with the lower zone 32 a and suitable forreceiving a gaseous phase.

As it is shown for example in FIG. 7, third tank 32 comprises at least agas inlet 33 fluidically communicating with gas inlet line 66 of gasrecovering circuit 10: gas inlet 33 is advantageously positioned inproximity with the third tank 32 bottom: in this way the recovered gasesintroduced in third tank 32 immediately contact the acid solution A inthe lower zone 32 a.

As it is shown in FIG. 7, third tank further comprises at least one gasoutlet 34 positioned at a top zone of third tank 32 and adapted tofluidically communicate the upper zone 32 b to a gas outlet line 35.

Acid solution A is configured to determine, following a contact withgases arriving from inlet 33, the salification of ammonia present insaid gases with H⁺ ions of said acid solution A and the formation of afirst flow of purified gas comprising nitrogen, having a percentagelower than the nitrogen percentage present in gases entering third tank32.

More particularly, acid solution A comprises, in a non limiting way, adiluted solution of sulphuric acid and distilled water or,alternatively, just sulphuric acid (H₂SO₄).

In a preferred embodiment, acid solution A comprises at least sulphuricacid and distilled water: sulphuric acid percentage present in acidsolution A is greater than or equal to the percentage of distilled waterpresent in the acid solution. Specifically, the ratio of the sulphuricacid percentage to the distilled water percentage present in the acidsolution is greater than 1, particularly greater than 1.5.

The chemical principle underlying this treatment, is related to thegreat capacity of the gaseous ammonia to solubilize in water, in whichthere are also SO₄=ions (due to the hydrolysis of water which shifts thechemical equilibrium of the acid dissociation) by forming a molecule ofammonium sulphate [NH₄ ⁺]2SO₄ (the reaction is exothermic and,therefore, generates thermal energy: the temperature shifts theequilibrium of the reaction of the acid in the distilled water). In thisway, it is possible to capture the ammonia gases for forming ammoniumsulphate (H₂SO₄+2NH₃═[NH₄ ⁺]2SO₄), which is a stable salt andprecipitates, when the concentration is averagely greater than 30% wt.,particularly is greater than 50% wt., still more particularly is about63% wt. (this factor varies according to the temperature and pressure inthe system and atmosphere).

Refining tank 32 comprises a filtration element 37 arranged in the upperzone 32 b; such filtration element 37 is configured to intercept thefirst purified gas flow and enable the formation of a second purifiedgas flow comprising a nitrogen percentage less than the nitrogenpercentage present in the first purified gas flow.

Filtration element 37 substantially comprises a recovery plateconfigured to receive first gas flow exiting acid solution A and enablethe condensation: the step of condensing at least a portion of the gas,enables to form a liquid which, falling from plate 38 towards acidsolution A, enables to further abate gas comprising nitrogen.

Liquid falling from recovery plate 38, meets first gas flow containingnitrogen (particularly ammonia) ascending towards the recovery plate;because the gas, particularly ammonia NH₃, easily bind to thecondensate, the latter defines at least one liquid, particularly NH₄ ⁺,which falls again inside the lower zone 32 a of third tank.

In this way, second gas flow contains less nitrogen gas so that it ismore purified than first gas flow. Advantageously, recovery plate 38 isperimetrally countershaped to the compartment defined by lower zone 32b. The condensation reaction of a portion of gas, on the plate, iscaused by a pressure increase of said gas generated by the plate and/ortemperature of the latter.

The pressure increase of the gas flow ascending towards the upper zoneis mainly caused by the choke defined by the recovery plate 38 whichsubstantially reduces the gas cross-section. FIG. 7 schematically showsa first embodiment of third tank 32 having a supply conduit for thegases recovered in first and second tanks, merging at the top of secondtank 32, and substantially extends at the bottom wall of the latter,where it defines gas inlet 33.

In the embodiment of FIG. 7, the recovery plate has an arched bodyhaving a concavity facing the lower zone 32 b of third tank.

In an embodiment variant of third tank 32 shown in FIG. 7A, third tankhas a conduit supplying gases, directly leading to the bottom wall (thepassage of the conduit inside the tank itself is absent) on which it isdefined the gas inlet 33.

Inside solution A, in a non limiting way, it is arranged a series ofintercepting elements 73 configured to define a zigzag path. The gas,introduced from inlet 33, ascends towards the recovery plate along thetortuous path.

It is useful to specify that gases introduced inside third tank 32 form,in the liquid solution, micro bubbles containing, for example, NH₃ andO₂ gases. The zigzag systems are for deforming the bubbles and increasethe contact between the gases free in the micro bubbles, and the wallsof the same, the latter contacting the acid solution; this enables acidto capture NH₃ molecules on all the surface of the bubble with acontinuous exchange between liquid/gas.

The deformation process, caused by the tortuous system, causes acontinuous inner exchange of the gases. Specifically, the continuousbubble deformation causes a distribution of new NH₃ molecules at thecontainment surface of the micro bubble: in this way, the acid solutioncan capture new NH₃ molecules in order to purify the gas flow introducedin the tank.

More in detail, the micro bubble, due to the surface tension, maintainsits shape, and therefore gives ammonia gas to the acid solution so thatthe gas, exiting from acid solution, will be strongly purified.

As it is shown in FIG. 7A, third tank 32 comprises, in a non limitingway, a temperature sensor 74 and pH sensor 75 suitable for contactingthe acid solution A and detecting temperature and pH, respectively.

Third tank, of FIG. 7A, further comprises a level sensor 76 adapted tomonitor the level reached by the acid solution A inside third tank.

FIG. 6 shows, in a non limiting way, an embodiment of apparatus 1comprising only one tank 32. More particularly, apparatus 1 can comprisea plurality of refining tanks 32 consecutive to each other andfluidically communicating (in cascade) to each other, configured toobtain purified gases having lower and lower ammonia contents.

As it is schematically shown in FIG. 8, apparatus terminates with one ormore active carbon filters 39 adapted to receive the flow of purifiedgas exiting the last refining tank, in order to substantially enable tototally purify the gases before releasing them in the atmosphere.

It is useful to specify that the sewage energising by the microwavegenerator and/or electrolytic cell and/or ultrasound generator, enablesto oxidize/reduce also other groups of substances included in the carbonchemistry.

More particularly, the energy transferred to the system, besidesenabling to agitate the molecules of the nitrogen group (both the freemolecules, as NH₄, or bound to carbon molecules as amines), alsoagitates the carbon bonds (both as single, double or triple bonds). Thisenables to reduce (to shorter chains and more easily biodegradable) longcarbon chains (for example, linear hydrocarbons, alcohol, ketones,aldehydes, and alkanes and derivatives thereof, alkenes and derivatesthereof, generic organic acids, proteins/amino-acids, sugars, vitamins)to more shorter chains and easily manageable for depuring from thechemical and biological point of view.

Such phenomenon is also effective for groups of cyclic and aromaticcarbon chains, such as for example: phenols and polyphenols,cyclic/aromatic hydrocarbons, heterocyclic compounds.

De facto, in this way it is possible to “break down” the complex organicsubstance so that it can take a “simplified” form both for thedepuration, and the production of renewable sources, such as biogas.

For this object, it is particularly useful to blow nitrogen in sewage,which in turn smooth the oxidation/reduction processes of the organicsubstance because it is directly solubilized in the solution before theelectromagnetic treatment.

Effectively, apparatus 1 degradates the organic substance and enables torelease, as gas, substances such as nitrogen (as ammonia and gaseousphase) which is a molecule limiting the biological depuration processes(ammonia intoxicates the bacteria responsible for the depuration becauseit reduces the degradation-digestion) and for the biogas production.

The recovery of the organic substances is more easier and lesstroublesome from the chemical and biological point of view by depuringthe sewage of these easily volatile gases.

This can be a real and effective treatment for zootechnical sewage,organic sewage of industrial and residential origins, effectively, theuse of this apparatus promotes the depuration processes and theproduction of biogas, especially of complex substances such as forexample: sewage obtained by pressing products for producing vegetableoils (olives, generally seeds, etcetera), sewage obtained from poultryfarming for producing meat and eggs, sewage obtained by the butchering,dairy production, treatment of organic urban wastes, agro industrialtreatments, sewage obtained from residential and industrial foul water,sewage obtained from residential and industrial treatment containinghydrocarbons, alcohols, and all those carbon-based substances bothlinear, cyclic or aromatic.

Effectively, the apparatus, besides enabling to abate nitrogen presentin sewage, offers a depuration treatment capable of substantiallyshorten, with a very limited power consumption, the oxidation/reductionreactions, which in turn promote the depuration of organic sewage ortheir recovery for producing renewable sources such as biogas (both forthe use of dry matter and the use of liquid mass in digestors), or forproducing compost.

Moreover, the apparatus promotes the carbon cycle, so that the processed(or digested) substances can return to the compost chain production(without any polluting consequence) for an agricultural or environmentaluse in order to counter the desertification phenomena of theagricultural areas and increase a general fertility of soils.

Method of Treating Sewage.

It is also an object of the present invention a method of treatingsewage.

Such method provides a step of withdrawing sewage by first pump 47 andsupply the latter to a withdrawing line 44. Then or simultaneously tothe sewage withdrawing step, it is provided a step of withdrawing waterby a second pump 48 and supply said water to a supply line 45. Sewageand water can be supplied to first or pre-treatment tank 5 wherein thesewage is mixed with water. Mixing step can be performed inside firsttank 5 and/or inside an inlet line 46, where withdrawing line 44 andsupply line 45 merge.

First tank 5 is supplied, in a non limiting way, with a predeterminedsewage amount to be treated. After the sewage supply, the methodcomprises a step of pre-treating the sewage present in first tank 5 bytwo or more of the following treatments: an ultrasound treatment, amicrowave electromagnetic treatment, an electrolytic process.Specifically, pre-treatment step comprises an electrolytic treatmentstep and energy transfer step, particularly a temperature raisingtreatment. As previously discussed, electrolytic transfer and energytransfer steps (pre-treatment step) cause the dissociation from sewageof gases comprising nitrogen, particularly ammonia, thanks to a sewageoxidation and/or reduction process.

More particularly, the predetermined sewage amount treated during thepre-treatment step, has a volume greater than 0.5 m³, particularlycomprised between 1 m³ and 50 m³, still more particularly comprisedbetween 1 m³ and 10 m³. The pre-treatment step duration takes more than3 minutes, particularly is comprised between 3 and 300 minutes, stillmore particularly is comprised between 30 and 120 minutes.

As said, pre-treatment step provides an electrolytic step, whichcomprises a substep of positioning at least two electrodes 11 at leastpartially contacting the predetermined sewage amount present in firsttank 5 and electrically connected to at least one electric powergenerator 12. Generator 12 has an electric power greater than 1 kW,particularly has an electric power comprised between 3 and 20 kW, stillmore particularly has an electric power comprised between 5 and 15 kW.

Electric power generator 12 determines on electrodes 11 a potentialdifference determining an electric current flow in fluid. The electriccurrent flow substantially determines an inverse electrolysis processwhich, thanks to the electric current transfer in the fluid, causes achemical reaction in the same. Such reaction enables to release fromfluid at least a gas comprising nitrogen, particularly at least ammonia.Based on the chemical reaction in the fluid, in other words based on theobtained dissociation level, it is obtained a predetermined electriccurrent intensity. Particularly, the electric current intensity flowingthrough said fluid is greater than 4 Ampere, particularly is comprisedbetween 4 and 25 Ampere, still more particularly is comprised between 5and 20 Ampere.

Simultaneously with the electrolytic treatment step, the methodcomprises the energy transfer step, in other words a sewage heatingstep. This step comprises a microwave electromagnetic treatment step anda step of blowing inside the predetermined sewage amount at least onegas having a temperature greater than the temperature of the sewage tobe treated. Heating step enables to raise the temperature of thepredetermined amount of sewage present in first tank to a temperaturecomprised between 30° C. and 90° C., particularly between 35° C. and 85°C., still more particularly between 40° C. and 80° C. Theelectromagnetic treatment step has a strong sterilizing power both dueto the consequent temperature increase and due to the bactericidal andsporicidal powers of microwaves. As previously mentioned, sewage heatingstep can be performed, in a non limiting way, by a microwaveelectromagnetic treatment step and a step of blowing air warmer thansewage.

The microwave electromagnetic treatment step comprises the microwavegeneration by at least one microwaves generator 9 a, particularly amagnetron. Microwave generator 9 a is configured to generate waves at afrequency comprised between 1 GHz and 4 GHz, particularly between 1.5GHz and 3 GHz, still more particularly between 2.3 GHz and 2.6 GHz.

Blowing step comprises a gas introduction, particularly air, inside thesewage at a temperature greater than the one of sewage to be treated.More specifically, blowing step comprises an air introduction inside thepredetermined sewage amount, at a temperature comprised between 30° C.and 90° C., particularly between 35° C. and 85° C., still moreparticularly between 40° C. and 80° C. The heated air introductioninside the sewage promotes, besides the heating, also the oxidation ofthe organic matter. The gas blowing step inside the predetermined sewageamount comprises a substep of cooling the microwave generator 9 a by anair flow: the air flow exiting the generators 9 a cooling step isrecovered and used for the blowing step. Therefore, sewage heating andoxidation comprise a substep of reintroducing inside the sewage the airexiting the microwave generator 9 a cooling step.

The method comprises, at least during the electrolytic treatment and/ormicrowave energy transfer step, a step of mechanically stirring thepredetermined sewage amount. Stirring step comprises stirring thepredetermined sewage amount by a stirring device 20, for example a helix21 connected to an electric motor 22.

Stirring sewage enables to homogenize the sewage present in first tank 5in order to make more effective the operation of electrolytic and energytransfer processes. Keeping constant the stirred sewage amount countersthe generation of “counter-electromotive forces”, which could stabilizethe electrochemical process as the time goes by, reducing the capacityof degradating the organic substance. During the pre-treatment step, atleast part of sewage present in first tank is caused to continuouslyrecirculate inside a closed circuit.

During the sewage recirculation step inside the closed circuit, thelatter passes through at least one forced passage; at least one betweenthe electrodes pair and microwave generator is arranged at the forcedpassage so that it respectively enables to transfer energy to sewagepassing from forced passage in order to promote the separation fromsewage of gases comprising nitrogen, preferably ammonia.

Particularly, during the sewage recirculation step in the closedcircuit, the sewage is forced to pass through a plurality of consecutiveforced passages 17 and is irradiated by microwaves; the irradiationsubstep uses electromagnetic waves generators 9 a operative on a seriesor on all the forced passages 17. During the step of forcedly passingsewage, sewage currents of limited thickness are formed in thecorresponding forced passages 17, the thickness being not greater than 7mm, particularly not greater than 5 mm, said currents are facing atleast one corresponding microwave generator 9 a so that they arecompletely crossed by said electromagnetic waves.

It is useful to specify that at least one of the electrolytic treatmentand energy transfer steps can be performed on the predetermined sewageamount present in first tank and/or on sewage passing from the closedcircuit.

After the pre-treatment step, at least a portion of the predeterminedsewage amount is supplied to a second tank 23. Sewage, withdrawn fromfirst tank and sent to second tank, has a volume of at least 0.5 m³,particularly of 1 m³, still more particularly of 5 m³. Specifically, theratio of the sewage volume present in first tank during thepre-treatment step to the sewage volume withdrawn and supplied to secondtank, is greater than 2, particularly greater than 3, still moreparticularly greater than 4.

During or following the step of withdrawing a portion of thepredetermined sewage amount from first tank, method comprises a substepof integrating energy in first tank with not treated sewage, formaintaining substantially constant the predetermined sewage amount infirst tank. More particularly, during the step of withdrawing at least aportion of the predetermined sewage amount, method comprises a step ofsupplying a not treated sewage amount to first tank substantially equalto the amount withdrawn from first tank and supplied to second tank.Sewage present in second tank is subjected to an energy transfer stepcomprising at least one ultrasound treatment step (following theelectrolytic and thermal treatment steps) suitable for promoting thedissociation from sewage of gases comprising at least ammonia.

The sewage ultrasound treatment step comprises irradiating sewage byultrasonic waves having a frequency greater than 20 kHz, particularlycomprised between 25 kHz and 45 kHz, still more particularly between 30kHz and 35 kHz. The ultrasound treatment has a duration comprisedbetween 30 minutes and 300 minutes, particularly comprised between 30minutes and 120 minutes.

During the ultrasound treatment step, method comprises a step of blowingat least one gas inside the sewage adapted to promote the oxidation ofsewage and the separation of gases comprising ammonia from the sewageitself. The gas blown during the sewage ultrasound treatment step,comprises air, particularly comprises oxygen and/or ozone.

Blown gas besides enabling a further oxidation of the organic matterpresent in second tank 23, promotes the outflow from sewage of gasescomprising nitrogen.

Moreover, the method comprises, in a non limiting way, a sewageoxidation step. Specifically, at least a portion of the sewagedischarged by second tank 23, at the end of the ultrasonic treatment, issupplied to oxidation tank 77. Sewage withdrawn from second tank 23 iscaused to circulate in tank 77 simultaneously with a step of blowing airand/or nitrogen inside the circulating sewage. Blowing air and/onitrogen promotes the oxidation of sewage with a consequent dissociationof at least a portion of nitrogen contained in the latter.

Further, method comprises a step of separating gases comprisingnitrogen, preferably ammonia, from sewage present in tanks 5, 23 and 77(first, second and oxidation tank, respectively) and a following step ofrecovering said gases inside a gas recovering circuit 10.

Moreover, the method provides at least a step of refining the collectedgases adapted to purify said gases from nitrogen, particularly ammonia.The refining step comprises a step of blowing said collected gasesinside at least a third tank 32 containing an acid liquid solution A.

The liquid acid solution A comprises at least one diluted solution ofsulphuric acid and distilled water or sulphuric acid. More particularly,acid solution A comprises distilled water and sulphuric acid, whereinthe ratio of the sulphuric acid percentage to distilled water percentagepresent in the acid liquid solution is greater than 1, particularlygreater than 1.5.

Blowing gases inside solution A enables to form ammonium salts by thesalification of the ammonia bond present in the collected gases with H⁺ions of the liquid acid solution. The salification of at least a portionof the collected gases generates inside third tank 32 vapours containinga percentage of ammonia smaller than the percentage of ammonia of saidcollected gases.

After the first gas flow formation, there is a step of abating theammonia possibly present in first purified gas flow for forming a secondpurified gas flow containing an ammonia percentage smaller than thepercentage present in first gas flow.

Particularly, the step of abating ammonia comprises a step of providingat least one filtration element 37 inside third tank and particularlyarranged above the acid solution A.

De facto, first gas flow contacts filtration element 37 which promotesthe condensation of vapours of said gas for forming at least one liquidcomprising, for example, water H₂O and ammonia NH₄ ⁺: the liquid, byprecipitating in the acid solution A, contacts the first gas flowascending towards the filtration element 37. The substantial capacity ofthe ammonia gas to bind with the liquid (condensate) falling fromfiltration element 37, enables to dissolve gaseous ammonia of firstpurified gas flow for forming gases depurated from ammonia gases. Inthis way, there is the formation of said second gas flow. The method cancomprise a plurality of steps of said refining steps consecutive to eachother for obtaining purified gases having lower and lower contents ofammonia.

Besides the purification of gases, the method comprise at least one stepof chemically filtrating the purified gases outflowing from the latterrefining step by means of active carbon filters. In this way, it ispossible to release the gases generated during said method for treatingsewage in the atmosphere.

The method can comprise cycles of rinsing the treatment circuit 2. Therinsing step comprises a step of stopping first pump 46, for preventingthe sewage from entering the treatment circuit 2, and a step ofsupplying water in the latter through the supply line 45. Apredetermined water amount is caused to continuously circulate betweenthe inlet 3 and outlet 4 of circuit 2. Apparatus rinsing cycles dependon the type of treated material, particularly depend on the sewageviscosity.

More particularly, the method can comprise a rinsing cycle, after anumber of cycles of a predetermined sewage amount, greater than 3,particularly comprised between 3 and 40, still more particularlycomprised between 3 and 15.

ADVANTAGES OF THE INVENTION

By the above mentioned method and apparatus, it is possible to implementa treatment capable of accomplish several applications for improving thepurification of gases outflowing from the treatment, by minimizing thepresence of microbial forms in sewage.

Effectively, such method/apparatus is capable of degrading sewage sothat the latter can be reused, for example as fertilizer, ensuring inthis way a complete abatement of microbial forms which could pass fromsoil to the cultivated food products.

Depurating sewage from ammonia is made very effective thanks to thecombination of the pre-treatment and treatment steps according to theinvention. Specifically, both the electrolytic and ultrasound treatmentstake advantage of the preceding microwave treatment and homogenizationstep obtained by the forced passages and mixing.

The described method/apparatus enables to purify sewage and the formedgases with a reduced energy consumption and consequently with limitedoperating costs. To this matter, the steps of using the gas cooling themicrowave generators for pre-heating the treated mass and also thechoice of transferring from first to second tank just a portion of themass contained in first tank are particularly interesting.

The invention claimed is:
 1. An apparatus for sewage treatment,comprising: at least one tank (13); at least one inlet branch (14) tothe tank (13); at least one outlet branch (15) from the tank (13); atleast one microwave generator (9 a) configured to subject sewage presentinternally of the tank (13) to at least one temperature raisingtreatment; at least a cooling circuit (19) of the microwave generator (9a); and, at least one blowing device (9 b) connected to the tank (13),said blowing device (9 b) being connected to an outlet (26) of thecooling circuit (19) and sending heated gases arriving from the outlet(26) of the cooling circuit (19) into the tank (13), wherein the tank(13) comprises a plurality of chokes (16), each choke defining arespective forced passage (17) for sewage, wherein the microwavegenerator (9 a) is externally engaged to the tank (13), at least at oneof the forced passages (17), the microwave generator (9 a) beingconfigured to generate electromagnetic waves in a direction of theforced passages (17), and wherein the tank (13) comprises, at each ofthe forced passages (17), at least one window (18) that isradio-transparent to frequencies of the electromagnetic waves (18). 2.The apparatus of claim 1, comprising at least one electrolytic cell (8)associated to the tank (13) and having: at least one pair of electrodes(11) extending internally of a volume defined by the tank (13) andconfigured such as to at least partially contact the sewage; and, atleast one electrical energy generator (12) connected to the pair ofelectrodes (11), the electrolytic cell being configured to energize atleast one part of the sewage present internally of the tank (13) andpromote oxidation and/or reduction of the organic material of the sewageby electrolysis.
 3. The apparatus of claim 1, wherein the microwavegenerator (9 a) comprises at least one magnetron (9 a) configured toirradiate the sewage present in the tank (13) by at least partiallycarrying out the heat raising treatment.
 4. The apparatus of claim 1,wherein the microwave generator (9 a) is configured to irradiate thefluid with electromagnetic waves having a frequency greater than 1 GHz.5. The apparatus of claim 1, wherein the forced passages (17) each havea height, measured in a direction perpendicular to an advancementdirection of the sewage, the height being comprised between 15 mm and 60mm, and wherein at least one window (18) positioned between themicrowave generator (9 a) and an electrolytic cell (8) is engaged at oneof the forced passages (17) and is configured to energize the sewagecrossing the one of the forced passages (17).
 6. The apparatus of claim1, wherein the gas blown internally of the tank (13) by the blowingdevice (9 b) comprises air, in particular oxygen and/or ozone.
 7. Theapparatus of claim 1, comprising: at least one bypass branch (53)hydraulically connected to the inlet branch (14) and the outlet branch(15); at least one discharge outlet (54) configured to place theinternal volume of the tank (13) in fluid communication with the bypassbranch (53); at least one intercepting element (55) operatively activeon the discharge outlet (54) and configured to be arranged in a firstoperating condition in which the intercepting element (55) preventspassage of the sewage through the discharge outlet (54), theintercepting element (55) being further configured to be arranged in asecond operating condition wherein the intercepting element (55) enablesthe sewage to pass through the discharge outlet (54).
 8. The apparatusof claim 7, comprising: at least one sensor that is operatively activeon the tank (13) and at least one control unit (49) connected to thesensor, the control unit being configured to: receive at least onesignal from the sensor; process the signal for determining at least oneparameter linked to the sewage circulating internally of the tank (13),the parameter being at least one of the pressure and the temperature ofthe sewage, wherein the control unit (49) is configured to determine,based on the signal received from the sensor, the presence of a cloggedcondition of the tank (13), the control unit (49) being connected withthe intercepting element (55) and being configured to send a commandsignal for commanding the first operating condition or the secondoperating condition, the control unit (49) being configured to arrangethe intercepting element (55) in the second operating condition afterthe clogged condition of the tank (13) has been determined in order toenable sewage to outflow from the bypass branch.
 9. The apparatus ofclaim 1, further comprising: at least one bypass branch (53)hydraulically connected to the inlet branch (14) and the outlet branch(15); at least one discharge outlet (54) configured to place an internalvolume of the tank (13) in fluid communication with the bypass branch(53); and at least one intercepting element (55) operatively active onthe discharge outlet (54) and configured to be arranged in a firstoperating condition in which the intercepting element (55) preventspassage of the sewage through the discharge outlet (54), theintercepting element (55) being further configured to be arranged in asecond operating condition wherein the intercepting element (55) enablesthe sewage to pass through the discharge outlet (54).
 10. The apparatusof claim 9, further comprising: at least one sensor that is operativelyactive on the tank (13) and at least one control unit (49) connected tothe sensor, the control unit being configured to: receive at least onesignal from the sensor; process the signal for determining at least oneparameter linked to the sewage circulating internally of the tank (13),the parameter being at least one of a pressure and temperature of thesewage; and wherein the control unit (49) is configured to determine,based on the signal received from the sensor, the presence of a cloggedcondition of the tank (13), the control unit (49) being connected to theintercepting element (55) and being configured to send a command signalfor commanding the first operating condition or the second operatingcondition, the control unit (49) being configured to arrange theintercepting element (55) in the second operating condition after theclogged condition of the tank (13) has been determined in order toenable sewage to outflow from the bypass branch.
 11. An apparatus forsewage treatment, comprising: at least one tank (13); at least one inletbranch (14) to the tank (13); at least one outlet branch (15) from thetank (13); at least one microwave generator (9 a) configured to subjectsewage present internally of the tank (13) to at least one temperatureraising treatment; at least a cooling circuit (19) of the microwavegenerator (9 a); at least one blowing device (9 b) connected to the tank(13), said blowing device (9 b) being connected to an outlet (26) of thecooling circuit (19) and configured to send heated gases arriving fromthe outlet (26) of the cooling circuit (19) into the tank (13); whereinthe tank (13) comprises a plurality of chokes (16), each choke defininga respective forced passage (17) of the sewage, wherein the microwavegenerator (9 a) and an electrolytic cell (8) are engaged at least at oneforced passage (17) and configured to energize the sewage crossing theforced passage (17).
 12. The apparatus of claim 11, wherein theelectrolytic cell (8) is associated with the tank (13) and has: at leastone pair of electrodes (11) extending internally of a volume defined bythe tank (13) and configured to at least partially contact the sewage;at least one electrical energy generator (12) connected to the pair ofelectrodes (11), the electrolytic cell (8) being configured to energizeat least one part of the sewage present internally of the tank (13) andpromote oxidation and/or reduction of the organic material of the sewageby electrolysis.
 13. The apparatus according to claim 11, wherein theforced passages (17) have a height, measured in a directionperpendicular to an advancement direction of the sewage, the heightbeing between 15 mm and 60 mm.